As a naturally curious person, I love learning new things. These discoveries don’t need to be world-changing, just mildly interesting.
Of course, Reddit is a great place for such discoveries, and one of my favorite subreddits for random knowledge is r/whatisthisthing. From day-to-day curiosity to weird mold to old devices, you can learn all about the strange things people have found and others have helped them identify.
1. After storing a mini-fridge for a friend, jedicowboyreddit wondered if the tan goop on the back was a problem.
Reddit | jedicowboyreddit
I get why they would be worried, but it’s actually just expanding foam insulation used inside the fridge parts to protect them from the cold. It was likely spilled during manufacturing and has since discolored.
2. “Found those things on my parent’s garden, it looks like eggs, it’s very squishy.” —oudatboi
Reddit | oudatboi
They are an example of blue-green algae, or nostoc, and should be cleaned up. Many forms of blue-green algae are toxic to animals and wildlife.
3. Here’s another example of how the algae can appear in a garden.
Reddit | forevertomorrowagain
Luckily, you can sweep or shovel away most of it easily. If it’s on a patio or laneway, rinsing the last bits away with bleach will help prevent it from coming back.
In lawn or gardens, you’ll need to improve drainage to prevent future blooms.
4. Redditor cheeze2000 asked: “What are these yellow sticky “salmon roe” along the corridor of my apartment?”
Reddit | cheeze2000
Comparing them to fish eggs is a pretty gross description, though apt, but thankfully these are just water beads from inside a sensory toy.
Once someone pointed it out, they realized they were from their cousin’s toy.
5. This strange device is on the wall of an apartment. The dials can be changed to say In or Out.
Reddit | Naffel
The space must have been an office at one point, since these used to allow coworkers to indicate when they were in their offices or not.
6. “What are these thin straight lines going across my tendies?” asked gamer_bread.
Reddit | gamer_bread
Don’t worry, they aren’t signs of tampering or weird manufacturing. They’re actually just marks from the rack hot tenders are put on to let the grease drain a bit before serving.
7. “Found in washing machine. Is this a part?” —Ekusin
Reddit | Ekusin
“Or some random something my daughter picked up during the day?”
Since it’s a filter for an automatic sprinkler, I’d say your daughter picked it up.
8. User rmajor86 wondered what the dashes on the road were for.
Reddit | rmajor86
They are steel dowels put in to reinforce the pavement where different sections join. It helps balance the load when vehicles move from one concrete panel to the next.
9. Sometimes you see someone using a tool you never knew existed.
Reddit | arcthadon
Such as this device used to put the GUCCI logo on the shoe. It’s a handheld laser printer, which is pretty darn cool.
10. “What are these? I can’t seem to get an answer from my parents.” —chettybang209
Reddit | chettybang209
Don’t know why the parents wouldn’t answer, unless they were embarrassed not to know that they are Clackers. They are a toy basically meant for bored kids to drive their parents mad.
Like a fidget spinner, but with risk of bodily harm.
11. One person wanted to know what this small bead was inside the filter of their Winman Blues Menthols.
Reddit | gravyboy98
It’s more menthol. Since there was already some flavor, the person probably didn’t realize it could be even smoother if they squished the filter just enough to crush the little menthol bomb.
12. “My wife said she found this in the dish washer!” —MyleSton
Reddit | MyleSton
The metal thing, not the Sharpie, presumably — can you imagine the mess if a Sharpie went through the dishwasher?
The metal piece is the needle of a meat injector.
13. Sometimes you’re just curious about a small detail you see every day, like why the prongs have holes in them.
Reddit | one_pipey_boi
The holes actually help keep the device plugged in, as the outlet has little nubs inside that sit perfectly in them.
That’s how big charging blocks like the one shown don’t succumb to gravity when held in place by two short prongs.
14. This solar-powered device seems to just be a microphone chained to a pole.
Reddit | ValkyriesAreReal
And it sort of is. The microphone collects the ambient sound so that city planners can see how much noise pollution is in a given area.
15. Like many people moving into new homes, DarthRuby was baffled by some old wiring.
Reddit | DarthRuby
In this case, it’s pretty simple. At some point, the house had fiber optic lines added and these are the spots where the installers had to run them in and out of the walls.
16. “What is this part of a Viking range?” —seaniebearxx
Reddit | seaniebearxx
As someone who has only ever had electric stoves, this would baffle me too. It’s a drip tray for collecting anything that falls through the burners.
17. If you’ve received a random package from Amazon, know that you aren’t alone.
Reddit | buddyandfinn
They’re part of a reviews scam called “brushing”. By sending out a whole bunch of super-cheap items to random people, companies can trick Amazon into thinking it’s an actual sale, allowing the company to create another fake five star review.
This particular doohickey is a phone stand.
18. SirPringles, who apparently lives in Scandinavia, came home to this display on their front door.
Reddit | SirPringles
This slimy mass making it a challenge to unlock the door is exactly what it looks like: a bunch of slugs. Apparently they’re known to huddle together for warmth and to save moisture. Yum.
19. “A friend who runs an antique shop found this today. That’s all the info I have,” wrote shelrayray.
Reddit | shelrayray
So, this is what you use to sharpen razor blades. You run the blade between the two little balls a few times to get that satisfyingly fine edge back.
20. “My dad found this ‘alien pod’ in the yard and gave it to my mom to put in her terrarium, because they’re weirdos. What is it?” asked -MayorOfTheMoon-
Reddit | -MayorOfTheMoon-
Okay, it’s not weird to want variety and real examples of flora and fauna in your terrarium. But it might be a bit weird to put things in there when you don’t know exactly what they are.
Turns out this is a moth cocoon that hasn’t hatched just yet. They might want to put it back outside.
21. As oddly gruesome as it is clinically fascinating, PjSnarkles says this was found inside cremated remains.
Reddit | PjSnarkles
It’s strange that it wasn’t consumed in the cremation process, but this, sadly, is a chemo port, which tells an all-too-familiar tale.
22. Redditor iloveallthestuffs says their “Russian immigrant Grandfather left this for me.”
Reddit | iloveallthestuffs
This beautiful bank note for 500 rubles was issued back in 1912, under an empire that ceased to exist five years later, so it’s probably worth more as a work of art than anything else.
23. Redditor kha_id wasn’t too sure who would have carried this badge.
Reddit | kha_id
From the same neck of the woods as that bank note — but obviously a different era — this is a Soviet neighborhood watch badge.
24. I wouldn’t be sure what to make of a rusty old box with two lighbulbs plugged inside of it either.
Reddit | cstanford94
But as cstanford94 discovered, it’s an old school lightbox. It’s the sort of thing used for contact printing and developing film.
25. Redditor mjoness96 was concerned about a strange wire under her dresser.
Reddit | mjoness96
This is just an old wire that was likely used for a phone line or HVAC system. Considering the shape it’s in and the style of connector, it’s unlikely to be part of any modern surveillance system.
26. The redditor who uploaded this pic thought it might be of a “large format camera lens.”
Reddit | Timallenisanarc420
Not a bad guess, and not far off the mark, it’s a lens all right — but it’s for a theater spotlight, not a camera.
27. “Found in mens toilet in work. About 20cm long. Did not touch,” wrote scottp_15.
Reddit | scottp_15
Wise move, the not touching, because this is a catheter. Not sure why someone would just leave it sitting there like that, however. Yikes.
28. “They’re on some street corners in Australia!” said sampebby. They’re lots of different sizes and all look “hole-punched”.
Reddit | sampebby
They are weights from a “sandbag” used to hold down things like cafe umbrellas.
29. Rossracing, who says he’s a garbage man, found this thing that definitely has a protractor-like element on it.
Reddit | rossracing
Old school engineers might be more familiar with this tool, a clinometer, which is used in surveying to gauge grades for roads and the like.
30. JonaldJohnson noticed these small pink tags on walls around Hoover Dam.
Reddit | JonaldJohnston
And it turns out they would go nicely with that old clinometer, because they’re targets for surveyors to monitor how large structure settle or move around.
31. This unusual doll was clearly made this way on purpose.
Reddit | GreenTower
And as GreenTower discovered, it’s a Ukrainian kozak, or cossack, doll. They’re known for their long, flowing mustaches, and it looks like this one has seen better days.
32. Any post that starts with “I was cooking pork ribs yesterday and this was hanging out of one” doesn’t bode well.
Reddit | jchimes
“After boiling + cooking I found this white (half was sticking out and half was stuck) worm things. It has a red vein in it. Anyone know what it is?”
I hate to tell you this, but it’s most likely some form of roundworm. Thankfully, they noticed before eating and should probably inform the supermarket/butcher that they purchased the meat from.
33. Avocadoavenger wanted to know why this jug had tiny holes in the top.
Reddit | Avocadoavenger
It almost looks like salt shaker or some such device, but those holes are intended for flower stems to keep an arrangement in place and looking nice.
34. Redditor shadfitz7 found these two brass things on a job site.
Reddit | shadfitz7
They described them as “crescent moons with detailed tooling engraved on both of them.” They look almost like they could be part of some cufflinks to me, but they’re actually brass embossing dies.
35. Redditor mchgndr found this mossy old antique “deep in the woods in Michigan.”
Reddit | mchgndr
The eagle eyes of Reddit were able to see through the age and the wear and the moss to determine that this is an old radio.
36. Redditor bnfvd had a clue to work with for this one: it was in a dentist’s office.
Reddit | bnfvd
Which makes sense, because it’s an old-timey dental drill. Note the foot pedal that powers it. Really makes you appreciate modern dentistry, doesn’t it?
37. Thrift store finds can be pretty perplexing — and bizarre.
Reddit | redlotusaustin
For example, this partial spine on a mount that redlotusaustin found at Goodwill. Redditor Lazarus_Rat was able to identify it as belonging to a cow.
38. A friend brought this trinket back from Peru for Emazing96, and it’s not entirely clear what type of animal it’s supposed to be or what significance it has.
Reddit | Emazing96
Could be a dog, could be a cat, right? Nope, it’s a bull, specifically a pucara bull. Locals keep these around the house as symbols of luck, fertility, and prosperity.
39. Sometimes you get random bonus items in packages, like copperdigger did.
Reddit | copperdigger
This thing came in an order of Mega blocks with nothing on the order sheet or markings to give clues. It’s a sink saddle, used to prevent damage to either sinks or dishes as you wash them.
40. If there were little black specks falling out of my ceiling, I’d want to know what they were from, too.
Reddit | DiMoSe
And the unfortunate news for DiMoSe is that they’re termite droppings. I guess that’s better than not knowing they’re at work and finding out an even harder way.
41. It’s sad that these ‘hooks’ that MyGrimyGooch found are even necessary.
Reddit | MyGrimyGooch
In the ‘up’ position, they can hold a little weight, like a towel. But with enough force, they’ll flip down — it’s a safety measure to keep people from harming themselves.
42. This “backwards snail” has been baffling smellfoy_ for a long time.
Reddit | smellfoy_
This thing that “has been living in my parents living room forever” is pretty useful, especially for older eyes — that clear part is a magnifying glass meant to be used when reading books.
43. If it wasn’t wood, you’d think this was a bottle stopper.
Reddit | Mantalex
But, as Mantalex found out, it’s a dibber for planting seeds. The grooves along the sides indicate depth with the big gaps each being an inch apart.
44. “Found at friends house. Gold box with a wiggly back end. Driving us all bonkers,” wrote Guywithacattattoo.
Reddit | Guywithatcattattoo
And it would drive you bonkers, too, if you weren’t familiar with Chinese padlocks, which is probably a lot of us.
45. Okay_Fabricator found this in a “dry lake/pond bed in my hometown in South Carolina.”
Reddit | Okay_Fabricator
Those divots look too smooth and intentional to be a randomly natural feature. This was identified as a capstone for starting fires with bow drill.
46. Oh, the things you find when cleaning out a closet.
Reddit | PsychicDelilah
This just happened to be at the back of an astronomy department’s closet, and PsychicDelilah had no idea what she’d found.
It sure doesn’t look like astronomical equipment, but it turns out it is: It’s a precise chronograph, which was used to determine the time of transit of celestial objects over certain points of the Earth.
47. SweptySr found this thing at a rummage warehouse and said the workers couldn’t identify it either.
Reddit | SweptySr
But Reddit could! It’s a phony baloney medical device called a violet ray wand.
Following numerous lawsuits, their manufacture has been prohibited in the U.S. since the 1950s, but companies based outside the U.S. still make them.
48. After finding this in an old barn, MrdotPieman only knew this little ball wasn’t hollow and felt like clay.
Reddit | MrdotPieman
Oddly enough, this is an antique dating from the 1910s and 1920s — it’s a golf ball from a toy game, but not a real golf ball.
49. Also found in an old barn: this antique…something.
Reddit | dissociative-daisy
“It has a hand crank attached to what appears to be a cutting wheel with a funnel shaped surround,” wrote dissociative-daisy. It’s a kitchen tool used to pit cherries!
50. Redditor the spookylukey discovered this goo on a stick in Kentucky.
Reddit | thespookylukey
Apparently it’s a form of jelly fungus. Yeah, maybe don’t spread that on your toast.