AttackSpontaneous Explosion
Flip a coin. If heads, this attack does 10 damage plus 30 more damage and Koga's Weezing does 30 damage to itself; if tails, this attack does 10 damage.

Weezing is Pokédex #110, generation 1 (Kanto). Koga's Weezing is a Stage 1 Grass Pokémon with 70 HP. The card lists level 31. The card says it evolves from Koga's Koffing. In this catalog that name is Koffing (#109).
Koga's Weezing sits at 50/132 in Gym Challenge, position 50 of 132. Before it is 49 Koga's Pidgey, and after it is 51 Lt. Surge's Eevee. The set belongs to the Gym series. It was released on 16 October 2000. The printed size is 132, and the checklist is the same length. The listed rarity is Uncommon.
The attack Spontaneous Explosion lists 10+ damage. The cost is Grass, Grass. Flip a coin. If heads, this attack does 10 damage plus 30 more damage and Koga's Weezing does 30 damage to itself; if tails, this attack does 10 damage. Toxic Cloud is another attack lists 20 damage. The cost is Grass, Grass, Colorless. Flip a coin. If heads, the Defending Pokémon is now Poisoned. It now takes 20 Poison damage instead of 10 after each player's turn (even if it was already Poisoned). Weakness is Psychic ×2. Retreat cost is 2.
Weezing (#110) has 28 other cards in the catalog. Those other cards are in 24 sets. The other printings with a release date run from 1999 to 2025. The earliest other card is Weezing 45/62 in Fossil (1999). That card is named Weezing, while this one is Koga's Weezing. That card lists 60 HP, and this one lists 70 HP. Both list the rarity Uncommon. Mitsuhiro Arita illustrated that card, and Ken Sugimori illustrated this one. Retreat cost there is 1, and here it is 2. 26 other cards of Weezing list a different HP.
The illustrator line reads Ken Sugimori. I count 1,112 other cards in the catalog with that illustrator.
Gym Challenge set binder is where a full Gym Challenge set goes. This card fills one slot there. A generation binder holds one card of each species. Weezing can fill a slot in Generation 1 binder (Kanto). Themed lists that include this exact card are Trainer's Pokémon and Kanto Gym Leaders and their Pokémon. I still need this card.
Flip a coin. If heads, this attack does 10 damage plus 30 more damage and Koga's Weezing does 30 damage to itself; if tails, this attack does 10 damage.
Flip a coin. If heads, the Defending Pokémon is now Poisoned. It now takes 20 Poison damage instead of 10 after each player's turn (even if it was already Poisoned).
Gym Challenge, in the Gym series. It was released on 16 October 2000. The printed size is 132.
50/132. It is entry 50 of 132 in this checklist.
Ken Sugimori. The catalog lists 1,112 other cards with that illustrator.
Uncommon.
Weezing #110, generation 1 (Kanto).
Spontaneous Explosion (10+) and Toxic Cloud (20).