Cassidy. the Stoneviper

Echo Strike: Whenever Cassidy attacks, create a
token that's a copy of Cassidy; "If this creature
would leave the battlefield, exile it instead."
Exile that token at the end of combat.

Viper's Resilience: As long as it's your turn,
Cassidy has indestructible.

Commanding Roar{2}{r}: Cassidy deals 2 damage
to each opponent and each creature they control.
This damage can't be prevented.