I'm thinking of a thing; and you have to guess what it is by asking me only yes or no questions;
example:
"is it a person?"
"is it a type of food?"
winner hosts the next round. you may double post.
I'll start.
Is it larger than a car?
no
Does it have legs?
Can I eat it without risking my life?
does it have legs?: yes
Can I eat it without risking my life?: I believe you can however; I would never eat it myself.
Does it have more than 2 legs?
It has legs. Does it hike by the lake?
arttu98: yes
Pieuw: You wouldn't say it "hikes" really. It walks, it could be by a lake, but not always.
Can it climb trees?
Is it likely to try and eat you?
Does it have a largely undeserved association in popular culture with mass suicide?
Clam: yes [according to wikipedia]
namida: no
Proxima: no
Is it a type of rodent.
Is the first letter within A-M (including A and M)?
grams88: yes, scientists classify it as a rodent, although I would not if I was a scientist...
ccexplore: no
Does it live mainly in the Southern Hemisphere?
no
grams88: yes, scientists classify it as a rodent, although I would not if I was a scientist...
ccexplore: no
Hmm, not a Capybara then--actually it seems to rule out quite a few interesting rodents.
Alright then, so is the first letter within range of N-S (inclusive)?
yes
Is it a porcupine?
Is it a porcupine?
yes! ccexplore wins the internet!
Special thanks to grams88 for really helping to start narrow things down. I'm just glad I didn't have to do the letter thing over and over!

Hmm, so porcupines can climb trees huh? Yikes, imagine getting hit with a rain of spiny quills from above...

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Anyhow, I've thought of my thing. Ask away! Hopefully not too difficult, but if it turns out problematic, I can redo with a different thing by popular request.
Welldone to yourself ccexplore for guessing porcupines, I would of never thought of that one.
is it a living thing?
yes
is it someone on this forum?
no
Is it someone?
no
Is it an animal?
yes
Does it live in the sea?
yes
is it a clam?
no
is it a vertebrate?
no
does this animal have any kind of locomotion? [... in a general sense, I won't say "any kind at all" since this could be difficult to decide. eh, nevermind just answer however you want]
It's a good question given where the answers have led. And I don't think it's ambiguous in this case given
the definition of animal locomotion in Wikipedia. My answer would be a resounding "no".
does it begin with the letter M-Z?
Continuing my role as the guy who mostly ignores this topic, then drops in every now and then with a wild guess....
Is it coral?
Is it coral?
Dingdingdingdingding...!!! You got it!

Ha, and I love how mobius has started adopting my approach.
aw shucks, I was thinking either coral or sponge!
Okay, my turn

Ask away!
it is a living thing?
no
does it having moving parts?
If this question is too vague or hard to answer I'll forget it and ask a different one
Can you find it on Earth?
(this is quite a tricky one, so I'll allow myself to say more than just "yes" or "no" occasionally)
mobius: no
ccexplore: you can't find any exact ones
17 questions left
is it a tangible object?
what do you mean by 17 questions left?

edit:
-when was it discovered (or invented)?
Ha, and I love how mobius has started adopting my approach.
actually that's quite an effective way to narrow it down, I thought of trying that earlier but didn't get to it until then. I wonder what other kinds of tricks there are...