Diagnosis

Flying, firststrike, menace, deathtouch.
When Diagnosis enters,all opponents lose 4 life and sacrifice a creature with the greatest power among creatures they controls.
At the beginning of each unkeep,you can pay {u},{b}
or {r},untap Diagnosis and it gains hexproof and indestructible until end of turn.
Whenever Diagnosis deals combat damage to a player, that player lose half their life, rounded down.
When Diagnosis would leave the battlefield, transform into one of them instead.