Pookie

The mushroom dog is an Alien who chased Bender in 3012 as Bender approached a mansion.

Production
The mushroom dog was first seen in a character design - and part of the storyboard for "The Thief of Baghead" - released by Countdown to Futurama on 18 May 2012.

Trivia

 * The mushroom dog's description in the character design calls it "Mushroom Ego". This may be a misspelling.
 * The Countdown to Futurama post which introduced the mushroom dog jokingly mentioned a band which played at in 1997 - called "Mushroom Dog" - as not being the source for the character's name.  It is unknown whether or not the band is real.