Paralyze

The soft lock as ongoing economic pressure: that is the design idea here, and it predates the cleaner templates that eventually replaced it. Most aura-based lockdown effects since (Arrest, Pacifism, Faith's Fetters) simply turn the creature off. This one keeps the creature on the battlefield, taps it on entry, and then asks the opponent to pay four every upkeep to get it back. That four-mana ransom is the design discipline: it is almost never worth paying on a vanilla creature, which means the card reads as permanent removal, but the option exists, which means a sufficiently large threat can be freed at a cost the controller is supposed to be exploiting elsewhere. The "doesn't untap" clause does the structural work that modern auras delegate to "can't attack or block"; the upkeep payment is the relief valve that early design used in place of the cleaner "exile" or "enchanted creature has no abilities" lines that came later. The original team treated lockdown not as a binary on-off, but as a tax that recurs every turn, with the enchanted creature still a creature, still a permanent, still theoretically recoverable. That model did not survive long; the cleaner templates won. But the shape is here, fully formed, in a one-mana black common.