Unkillable Warden

When the warden reaches 1 HP, it gets stunned for a few seconds, giving the player time to escape.

However, this mechanic may encourage players to fight the warden to see this animation. To discourage this, here's a bonus feature:
When the Warden is healing, it'll suck in the player while also dealing damage. The souls in its heart would beat rapidly, as if it's sucking the player's soul. The player can still somewhat get away if they sprint away from the warden, but they would have some difficulty. 

In Creative Mode, this mechanic will not occur. If the warden is killed by a Creative mode player, it will actually die and not enter its regenerative state.