Tragic Clown Dog
From Homestar Runner Wiki
The Tragic Clown Dog is the mascot for Bubs' Concession Stand. Bubs hired Strong Bad to dress as the Tragic Clown Dog; this was his part-time job (or more accurately his part-part-part-part very part time job). Strong Bad soon quit so he could get back to his Lappy 486, which was about to run out of battery power. Pictures with the Tragic Clown Dog aren't free, as Bubs tried to charge Pom Pom and Coach Z 50 bucks, then 60 bucks for the privilege.
The suit is owned by Strong Bad, as Bubs made him purchase the costume when he was hired. Strong Bad briefly appeared inside the suit in The House That Gave Sucky Tricks, with make-up to make it appear evil.