Grell Philosopher

Theft in blue usually means taking the object; this takes only what the object can do, and lends it to a whole board of Horrors at once. The distinction matters more than it reads. Rather than gaining control of an opponent's artifact, it copies that artifact's activated abilities onto every Horror you control, and it renews the loan each upkeep. The mana-fixing clause is what turns this from a curiosity into an engine: because you can spend blue as any color to fire those borrowed abilities, an opponent's off-color activated ability becomes fully usable inside a mono-blue shell. The design leans on redundancy of bodies rather than a single stolen permanent, which changes the axis entirely: the more Horrors on the table, the more copies of that ability you get to pay for and activate in a single turn. A stumpy 1/4 that recurs the theft each upkeep is built to sit back, survive, and accrue value across turns rather than swing, and the "target artifact an opponent controls" clause means it stalls out completely against a board with no artifacts to point at. It is a tribal payoff wearing an artifact-hate disguise, rewarding a wide Horror count and a table full of activated-ability artifacts to strip-mine.