So, how's the ball lickin' coming along? Red Rocket, Red Rocket! Just sit tight and I won't have to shoot you. 
History
Mr. Shuggums was Deadpool's dog. When Wade went to Genosha in order to kill Mr. Sinister, he mysteriously appeared on the island after Deadpool crashed in an abandoned prison. The mercenary had lost his arm and had his neck twisted, Mr. Shuggums found the arm and made Deadpool chase him until he got it.
The canine later led Wade to where Rogue was being held captive by Blockbuster. After being saved, Rogue needed to heal, and Deadpool decided to give her his healing factor through skin contact, by kissing her. Wade fainted, and Rogue used his fighting skills to fight the army of Sinister's clone that approached. Wade woke up, still disoriented, and tried to help Rogue by launching a grenade to his enemies. The projectile was caught by Mr. Shuggums, who wanted to return it to Wade as it was a toy, exploding. The ground below Deadpool collapsed and Wade got his legs severed, falling to a hidden catacomb.
The dog was later found safe and sound in Wade's modified flying Sentinel boot, but it took flight before Wade could get on board. When Deadpool later used said Sentinel boot to stomp Mr. Sinister, Mr. Shuggums came out of the landed boot.[1]Trivia
- The mainstream Deadpool stated that he would be unfit to own a dog.[2]