Zim:(Try) to give him advice/ tell him his disguise is lame.
Dib:Tell him that his head isn't big;it's bloody GINORMOUS!!!
Gaz: Challenge her to a DDR match
GIR:Whack him on his head and see if it has any effect.
Tallest Red:Spray him with multiple super soakers.
Tallest Purple: Drag him into a closet and kiss him...
Keef:Punch his face; see if he is still smiling afterwards!
Skoodge: Call him and get him to help Zim.
Tak:Kill her. Like, really KILL her.
Professor Membrane: Call him an irresponsible bastard.