Credit: Cartoon Network

Adventure Time wraps up its marathon fifth season on Monday with a finale titled “Billy’s Bucket List.” The title refers to Billy, the beloved idol of Finn and Jake…who unfortunately kicked the bucket, the victim of a nefarious scheme concocted by nefarious antagonist the Lich. True to form, the Adventure Time finale features a guest-star voice performance by a ranking member of comedy nobility: SNL vet and Brooklyn Nine-Nine Golden Globe winner Andy Samberg plays Rap Bear, a rapping bear who raps and is a bear.

Don’t believe us? Check out this exclusive clip from the finale, wherein Rap Bear and Finn get their 8 Mile on.

Tune into Cartoon Network on Monday to find out the shocking results of the rap battle!