Administering a prank and the not admitting your own prank.
To pull the wool over someones eyes.
An act of spontaneous mischievousness set upon degrading a person who is none the wiser.
Riki did not tell mike about peeing into Mikes spa.
Mike has no idea about his spa being peed into but everyone else knows about it and thinks its hilarious.
Poor Mike has no idea.
Mike has been Rik-dawged.