Your search for "spontaneous mutation 100" revealed the following:
Spontaneous Mutation (Foil) (CMR) from Commander Legends, available at 401 Games Canada. Rarity: Common Finish: Foil Artist: Christopher Moeller Card Text:FlashEnchant creatureEnchanted creature gets -X/-0, where X is the number of cards in your graveyard.
Spontaneous Mutation (CMR) from Commander Legends, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: Christopher Moeller Card Text:FlashEnchant creatureEnchanted creature gets -X/-0, where X is the number of cards in your graveyard.
Spontaneous Mutation (EMN) from Eldritch Moon, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: Christopher Moeller Card Text:Flash (You may cast this spell any time you could cast an instant.)Enchant creatureEnchanted creature gets -X/-0, where X is the...
Spontaneous Mutation (Foil) (INR) from Innistrad Remastered, available at 401 Games Canada. Rarity: Common Finish: Foil Artist: Christopher Moeller Card Text:FlashEnchant creatureEnchanted creature gets -X/-0, where X is the number of cards in your graveyard.
Spontaneous Mutation (INR) from Innistrad Remastered, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: Christopher Moeller Card Text:FlashEnchant creatureEnchanted creature gets -X/-0, where X is the number of cards in your graveyard.
Spontaneous Mutation (Foil) (EMN) from Eldritch Moon, available at 401 Games Canada. Rarity: Common Finish: Foil Artist: Christopher Moeller Card Text:Flash (You may cast this spell any time you could cast an instant.)Enchant creatureEnchanted creature gets -X/-0, where X is...