Mind Harness

A one-mana steal effect that bills you to keep it: the cumulative upkeep is the lever that makes for control of an opposing creature defensible, since the cost ramps an extra generic mana per age counter every turn until it outpaces the value. The card is engineered as a tempo tool rather than a true Control Magic. The intended line is to take a threat, swing for a turn or two while your opponent is short a body, then let the Aura fall away once the tax gets ugly, ideally after you have already squeezed the advantage out of it. The color restriction sharpens that purpose: enchant only red or green creatures, the two colors blue was positioned against in its era, which frames the card less as a generic answer and more as a tuned response to the beatdown and ramp decks of the time. It belongs to a now-largely-retired family of pre-modern blue control effects (Steal Artifact and the various Control Magic riffs) where designers leaned on upkeep costs and tight enchant clauses to police effects that would be flatly broken if printed clean. Strip the escalating tax and this is a wildly undercosted mind-control spell for its narrow targets; the cumulative upkeep exists precisely to keep that from being true.