Based on the above user's avatar, what is the user?

[ghost_man]

a jellyfish

[Ad Bot]

[Uncle Bengs]

monerkrome snarke

[TristanLuigi]

Someone who tried to be the Mockingjay pin in the Hunger Games but then failed miserably.

[Moppy]

A person who is shy, and tries to hide when looked at, but isn't afraid to pop out and surprise someone some times.
Also likes to play peek-a-boo.