Cheapest priced copy (Double Masters 2022): $0.35 at Card Kingdom, near mint, their price list as of .
Lyev Skyknight 
Creature — Human Knight · 3/1 · Uncommon · Return to Ravnica · #179
Flying
When this creature enters, detain target nonland permanent an opponent controls. (Until your next turn, that permanent can't attack or block and its activated abilities can't be activated.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $0.59 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters 2022 | 246 | Common | $0.35 | $0.49 |
| RNA Guild Kit | 16 | Uncommon | $0.59 | — |
| Return to Ravnica | 179 | Uncommon | $0.35 | $0.49 |
6 rulings from Wizards of the Coast
- 15 April 2013The static abilities of a detained permanent still apply. The triggered abilities of a detained permanent can still trigger.
- 15 April 2013If a creature is already attacking or blocking when it's detained, it won't be removed from combat. It will continue to attack or block.
- 15 April 2013If a noncreature permanent is detained and later turns into a creature, it won't be able to attack or block.
- 15 April 2013When a player leaves a multiplayer game, any continuous effects with durations that last until that player's next turn or until a specific point in that turn will last until that turn would have begun. They neither expire immediately nor last indefinitely.
- 15 April 2013If a permanent's activated ability is on the stack when that permanent is detained, the ability will be unaffected.
- 15 April 2013Activated abilities include a colon and are written in the form "[cost]: [effect]." No one can activate any activated abilities, including mana abilities, of a detained permanent.