Last night, Jimmy Kimmel Live celebrated Halloween the way it was supposed to be celebrated — with grotesque costumes and Megadeth playing on stage. The iconic metal band went all out and got ghoulish in some of the best creepy costumes we’ve seen this year, revising tried and true classics like Frankenstein’s monster, Wolf Man and Count Dracula. The band played two songs, “Public Enemy No. 1″ and “Symphony Of Destruction” to close the epic show, which saw Kimmel (appropriately?) dressed as a monkey.