Unnatural Selection

Type-changing as a repeatable effect is the rare control lever that touches an axis most decks never defend: creature type itself. For one mana, the same activation can shut off a tribal lord's pump (a Goblin King does nothing for a Goblin you have just renamed a Squid), turn an opponent's army of one tribe into legal targets for your tribal removal, or flip a creature into something your own anthem or Coat of Arms suddenly recognizes. The design lives entirely in the breadth of what "creature type" gates, and the single restriction (you may not choose Wall) reads less as a balance check than as a fossil from an era when Wall still meant "cannot attack" by definition, before Defender split off as its own keyword. Most of the time that breadth lies dormant, leaving the card a sideboard footnote rather than a centerpiece; its value spikes only where tribal identity is doing real mechanical work on both sides of the table. The activation is also a clean answer to changeling and to anything that keys off being a specific type to gain a bonus, since renaming the creature severs the link for a turn. It is a toolbox answer wearing the costume of a build-around, and the line between the two is drawn by whatever the rest of your deck cares about types for.