Answer:
"The hide two things, but tell them you hid three things prank
Here's a roommate-specific example: hide their toothpaste and socks, but tell them you hid their toothpaste, socks, and comb. Reveal the truth whenever!
The put some plastic on the top of their shampoo bottle, then screw the top back on prank
It's a little corny, but it works. And it's easily reversible, so your victim (friend) won't lose any of their beloved producy"
"The make them a fake fried egg and French fries prank"