Omnibian [Dissension] Commander Anthology Volume II Search your library for a

Search your library for a creature card with converted mana cost X or less and put it onto the battlefield

Other Knight creatures you control get +1/+1 and have indestructible

then sacrifice it unless you pay its upkeep cost for each age counter on it

*Frankenstein*

Omnibian [Dissension] Commander Anthology Volume II Search your library for aSet: Dissension Type: Creature Frog Rarity: Rare Cost: {1}{G}{G}{U} {T}: Target creature becomes a Frog with base power and toughness 3 3 until end of turn. "This creature has hyperevolved chameleonic abilities. It no longer mimics its surroundings, instead forcing them to take on its form." Simic research notes