In need of a non-damaging prank

Question

At work me and this guy do randomn stupid pranks to each others car...

like we have done the embarassing window paintings/ writings saran wrap, caution tape... i need something to do to his truck that doesnt cost alot.

and no i do not have access to inside his car..

help me out please

Answer 1

put some ketchup or any other thick liquid under his door handle! very funny and cheap