The other downside is that to transform to Optimus Prime, Autobot Leader, Optimus Prime, Hero needs to die, which is not easy to do even as a sacrificial blocker in combat because of his 8 Toughness
Prison commanders accomplish this either by increasing your opponent's spell casting cost or taxing them for playing some sort of ability or interacting in certain ways
Acererak the Archlich Demilich Ebondeath, Dracolich Ellywick Tumblestrum Flameskull Grand Master of Flowers Icingdeath, Frost Tyrant Inferno of the Star Mounts Iymrith, Desert Doom Lolth, Spider Queen Minsc, Beloved Ranger Mordenkainen Old Gnawbone The Book of Exalted Deeds The Book of Vile Darkness The Deck of Many Things The Tarrasque Tiamat Xanathar, Guild Kingpin Zariel, Archduke of Avernus
Ninja of the Deep Hours #108 Foundations Jumpstart Change Version Ninja of the Deep Hours Creature Human Ninja Ninjutsu (, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.) Whenever this creature deals combat damage to a player, you may draw a card
It was restricted in Five Color
If you do, return that card to the battlefield under its owner's control at the beginning of the next end step