Garbage Boy

From the Super Mario Wiki

In Mona's Stage, this red-nosed chum hides in a garbage can. After the player strums Mona's electric guitar for the second time, he pops out of the can. At the concert, he hides behind Mona. When she takes off, he tries to spice things up but Vanessa knocks him away. He is also seen at the Hawt House when the characters arrive but all of them must arrive.