Can u tell some pranks from the girls playing each other in their dorm,on stage of on variety shows?

Yuri got some insects and animals as a fanmail and she put each one of them behind something. She put a rat behind a trash can with only its tail sticking out. Someone found the rat and screamed. Snsd was on this variety toon and they were talking about ghosts and she sneaked up behind one of snsd's members and zei boo! And everyone jumped. BOy, YUri can be quite a prankster if she wants to be one!

I'm not sure if its much of a prank,but Jessica takes pictures of the members undressing. According to what Sunny zei haha.^^