April O'Neil, Human Element Finish:Nonfoil Assassin spells you cast have

Assassin spells you cast have freerunning {B}{B}

Stagger — Whenever Lightning deals combat damage to a player

gain control of target creature that player controls for as long as they're the monarch

−9: Search your library for any number of Dragon creature cards

It becomes a 0/0 Elemental creature with vigilance and haste that's still a land

April O'Neil, Human Element Finish:Nonfoil Assassin spells you cast haveWhenever a player casts an artifact, instant, or sorcery spell, you create a Mutagen token. (It's an artifact with '{1}, {T}, Sacrifice this token: Put a +1 +1 counter on target creature. Activate only as a sorcery.')