Blacephalon (Sun & Moon Promos SM221)

Blacephalon — 110 HP — [P]
Basic — Ultra Beast

[P][C] Fireworks Bomb
Put 4 damage counters on your opponent’s Pokémon in any way you like. If your opponent has exactly 3 Prize cards remaining, put 12 damage counters on them instead.

weakness: [D]×2
resistance: [F]-20
retreat: 2

Illus. Shin Nagasawa
Sun & Moon Promos — SM221 — Promo

It slithers toward people. Then, without warning, it triggers the explosion of its own head. It’s apparently one kind of Ultra Beast.