Petrahydrox

Hexproof solved by inversion. Most untargetable bodies simply refuse to be targeted; this Weird invites the target and then leaves, bouncing itself back to hand the instant a spell or ability points at it. That makes removal worthless against it: a burn spell or a kill spell flips the creature back to your hand before it can resolve, and you redeploy it next turn for the same cost. What the trigger does not do is distinguish friend from foe. Your own auras, your own pump spells, your own combat tricks all snap it home just as cleanly as an opponent's removal, so the card refuses every form of investment. You cannot suit it up, you cannot grow it, you cannot protect it; you can only recast a bare 3/3 over and over. The hybrid mana symbol lets it slot into either blue or red without committing the manabase, fitting the school of guild-flavored creatures built to serve two colors at once. What it leaves behind is a body that is functionally immune to interaction and functionally immune to improvement in the same clause, a design that hands you a removal-proof attacker on the condition that it will never be anything more than what it is printed as.