Eminem

“...” Marshall Mathers aka Eminem, is a successful American rapper, songwriter, record producer, record executive, and actor.

It is not made clear how the Hosts got in contact with him, but in past episodes Blubbercast has gotten more extravagant guests, so it's easy to presume the show has a reputation.

Eminem  is quite quiet, and seldom comments on whats going on, but when he does talk the hosts seem to be impressed with his input.

In the Blubberverse, Eminem still released a diss-track on Donald Trump even though he never became president.

Death
Towards the end of S3E4, Zander unkowingly killed eminem when he forces his way into the recording through via an explosive. As a result, Eminem is silent the whole episode because he never got the opportunity to Max his audio to be put into the episode.