The Great Halfini is a magician who appears in the "Elmo the Musical" segment, "Repair Monster the Musical."
In a city park, Halfini inadvertently causes things to split into half, which Repair Monster Elmo tries to fix. Halfini explains that he's merely trying to cut his hot dog in half, but something is wrong with his wand. Elmo discovers it too is broken in half and finds the other half in his sleeve. Elmo repairs the wand and the two musically restore the park.