Rihanna celebrated her 24th birthday on Monday night at the Hearst Mansion in Beverly Hills.

Yeah, Bruno Mars, Chris Martin and Katy Perry were in the house, but the star of the show was really the cake.

It featured a replica of Rihanna, tummy down and ass up on what People magazine is calling a seashell, but what appears to us as a giant joint.

Wow. We don't think it takes a genius to figure out what RiRi wished for when she blew out the candles.

[Mirror]