mtg meren commander deck of Clan Nel Toth Graveyard Reanimation Sacrifice Magic If that cards converted mana cost is less than or equal to the number of experience counters you have Meren of Clan Nel Toth

Marcy: An Evil Tree (not a joke), Exdeath is one of the cooler villain designs

With cards like Kruphix, God of HorizonsKruphix, God of Horizons, Inga and EsikaInga and Esika, Xolatoyac, the Smiling FloodXolatoyac, the Smiling Flood, and others, you can spend a lot of mana on other players' end steps to ensure they don't have as many opportunities to disrupt your game plan and to allow you to keep your own disruption spells castable at a moment's notice

WieldChishiro's blade and cut down all who would stand before you

For online Magic, where changing a card can be done by altering some lines of code, this is much more common