The player above suggests a challenge. The player below answers and makes a challenge for the player below them. And so on.
Example:
P1: You have to climb a tower or die.
P2: I ride a rainbow unicorn to the top. You are being followed by a moster.
I'll start.
You are stuck in a locked mansion. What do you do?

Pick the lock and leave. xD
You are being dangled off a cliff.

Jump off. It was 2 inches high anyway.
You are stuck in school for the rest of your life. It is impossible to leave.

I died and left that way. :3
You're stuck in a dimension where nothing ever happens and there's nothing to do. Worst of all, you can't leave. Even if you die, you'll just respawn there.

Therefore, I don't exist. So there is no challenge.
You have to do an impossible and illogical math problem within 30 seconds. Even the question itself takes that long to read.

But I already knew it because I saw the answers. :X
You are about to be forced to eat something you hate.

There's about one gram of it.
You are trapped in a bottomless pit.

I superjumped out.
You are trapped underwater with no air source. Also, you can't breathe underwater. You have thirty seconds before you drown.

(I keep on fearing this game will end because of an impossible question)
I swim up. It was the baby pool anyway.
You are banned from the Internet. Forever.

I hacked into another system and got back.
(Lol the baby pool tho.)
You are tied down to train tracks. There's no one in sight for miles. You hear the train coming.

Even if I heard it, it was on a separate track. No harm done. My track was abandoned forever, giving me time to bite the ropes open.
You are being robbed by the most famous robber there is.

I take a selfie with him and post it all over the Internet. Soon after, the police arrest him.
You are trapped inside a peanut butter jar.

You never said there was a cap. I use the peanut butter to climb up.
You are invisible to everyone.

I troll everyone in sight

You are about to be eaten by a shark, And your very small

I falcon punch it. :I
A shark has eaten you. You are being digested.