Haunter (Base Set BS 29)

Haunter — 60 HP — [P]
Stage 1 — Evolves from Gastly

[P] Hypnosis
The Defending Pokémon is now Asleep.

[P][P] Dream Eater: 50
You can’t use this attack unless the Defending Pokémon is Asleep.

weakness:
resistance: [F]-30
retreat: 1

Illus. Keiji Kinebuchi
Base Set — 29/102 — Uncommon

Because of its ability to slip through block walls, it is said to be from another dimension.