You can see my most successful writhing in this clip
Azula, Cunning Usurper Azula, Cunning Usurper gives theft a controlling spin since it removes the creatures it steals
(Look at the top three cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.) Flashback (You may cast this card from your graveyard for its flashback cost
I think of Ghalta when I think of 12 Mana
A high-cost Character with 5|6 stats that can be used in slow decks, especially ramp ones, but he cant be inked, so thats a downside
If you're able to fill up your deck with cards that have additional triggers when they die, you can chain these abilities turn after turn to keep punishing your opponents until there's nothing left in play