funny pranks to play on adults? grown men? please help!?

[livelifehappily]

me and my 16 year old cousin are trying to think of pranks to play on our uncle. were at a beach house with my whole extended family, and we have been messing with him a lot, and we need some ideas for good pranks. thanks in advance!

 

[JackM]

butter the bathroom floor. as soon as he goes to take a shower hes done. tie all of his shoes together. lock him out of his room. let him fall asleep, then wake him up screaming and yelling. prank call people from his cell phone.

 

[Niki]

Put knox gelatin in the toilet water and when they pee in it it splashes all over them