Generous Gift [Secret Lair Drop Series] Digital Hazard When its power becomes 20

When its power becomes 20 this way

then mills three cards

When this card is Fusion Summoned: Target 1 face-up monster your opponent controls

Set: XY: Generations Type: Grass Rarity: Common Retreat cost: Colorless

Set: Fallout Type: Creature — Bear Mutant Rarity: Rare Cost: {X}{G}{G}{G} Vigilance

Generous Gift [Secret Lair Drop Series] Digital Hazard When its power becomes 20Set: Secret Lair Drop Series Type: Instant Rarity: Rare Cost: {2}{W} Destroy target permanent. Its controller creates a 3 3 green Elephant creature token. Alas, the meowtropolis was struck by a devastating catastrophe, leaving the ground littered with debris.