He is MAD, yup, M-A-D. Like alder the daredevil, jumping of cliffs just to say some crap on "Destiny" (and almost dying every time.)
In HeartGold and SoulSilver, he appears in the Celadon Department
Store to give the player some Sinnoh starter accessories. He can be
found again later, on Route 47. In Black 2 and White 2, he appears on
Route 18 staring out into the ocean. Once the player talks to him, he
decides to head to Driftveil City and takes his leave.
He also SOMETIMES gives items too...