Paralyze

Enchantment - Aura, B (1)
Enchant creature
When Paralyze enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.
At the beginning of the upkeep of enchanted creature's controller, that player may pay {4}. If he or she does, untap the creature.¹
Illus. Anson Maddocks

Gatherer Card Rulings [Nov 2009]

• 10/4/2004: Paying the cost is optional.
• 10/4/2004: Paralyze can be cast targeting a creature which is already tapped.
• 10/4/2004: The creature can only be untapped using Paralyze once per turn.
• 10/4/2004: Two Paralyzes are not cumulative. Paying either one will untap the creature.
• 9/16/2007: This is a change from the most recent wording. As was the case in the past, Paralyze itself has the last triggered ability, rather than granting that ability to the enchanted creature.

Format Legality	Legal in Vintage, Legacy Banned in Extended, Standard
Printings (6/24)	Fifth Edition (Common) Fourth Edition (Common) Revised Edition (Common) Unlimited Edition (Common) Limited Edition (Beta) (Common) Limited Edition (Alpha) (Common)