AttackNightmare
The Defending Pokémon is now Asleep.

Gym Challenge is a set in the Gym series. It was released on 16 October 2000. The printed size is 132, and the checklist is the same length. Sabrina's Haunter is 55/132, in position 55 of 132 on this checklist. Before it is 54 Misty's Dewgong, and after it is 56 Sabrina's Hypno. The listed rarity is Uncommon.
Sabrina's Haunter is a Stage 1 Psychic Pokémon with 70 HP. The card lists level 29. In the Pokédex this is Haunter (#093), generation 1 (Kanto). The card says it evolves from Sabrina's Gastly. In this catalog that name is Gastly (#092). The card lists Gengar, Gengar (#094) under evolves to.
Ken Sugimori illustrated this card. The same name is on 1,112 other cards in the catalog.
Haunter (#093) has 30 other cards in the catalog. Those other cards are in 28 sets. The other printings with a release date run from 1999 to 2026. The earliest other card is Haunter 29/102 in Base (1999). That card is named Haunter, while this one is Sabrina's Haunter. That card lists 60 HP, and this one lists 70 HP. Both list the rarity Uncommon. Keiji Kinebuchi illustrated that card, and Ken Sugimori illustrated this one. 16 other cards of Haunter list a different HP.
The attack Nightmare lists 20 damage. The cost is Psychic, Psychic. The Defending Pokémon is now Asleep. Shadow Attack is another attack lists no damage number. The cost is Psychic, Psychic, Psychic. Flip a coin. If heads, and if your opponent has any Benched Pokémon, choose 1 of them and this attack does 30 damage to it. (Don't apply Weakness and Resistance for Benched Pokémon.) Resistance is Fighting -30.
I keep a set binder for Gym Challenge, meant to hold every card of that set. This card is one slot in the Gym Challenge set binder. A generation binder holds one card of each species. Haunter can fill a slot in Generation 1 binder (Kanto). Themed lists that include this exact card are Gengar and the Gastly line, Trainer's Pokémon, Kanto Gym Leaders and their Pokémon, and Sabrina and her Pokémon. I still need this card.
The Defending Pokémon is now Asleep.
Flip a coin. If heads, and if your opponent has any Benched Pokémon, choose 1 of them and this attack does 30 damage to it. (Don't apply Weakness and Resistance for Benched Pokémon.)
Gym Challenge, in the Gym series. It was released on 16 October 2000. The printed size is 132.
55/132. It is entry 55 of 132 in this checklist.
Ken Sugimori. The catalog lists 1,112 other cards with that illustrator.
Uncommon.
Haunter #093, generation 1 (Kanto).
Nightmare (20) and Shadow Attack.