--which is an edible Exxon Valdez surrounded by a number of "oil-covered" Peeps.
The party was for someone's birthday, but apparently it was also the anniversary of the Exxon Valdez oil spill. Mike's roommate decided to tastefully acknowledge the occasion with a cake. (I believe this was also the roommate that made the theme of their Halloween party "Offensive Halloween costumes.")
So yeah, that explains that.