Cheapest priced copy (Return to Ravnica): $0.35 at Card Kingdom, near mint, their price list as of .
New Prahv Guildmage 
Creature — Human Wizard · 2/2 · Uncommon · Return to Ravnica · #181
{W}{U}: Target creature gains flying until end of turn.
{3}{W}{U}: 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 inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Return to Ravnica | 181 | Uncommon | $0.35 | $0.49 |
6 rulings from Wizards of the Coast
- 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 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 noncreature permanent is detained and later turns into a creature, it won’t be able to attack or block.
- 15 April 2013The static abilities of a detained permanent still apply. The triggered abilities of a detained permanent can still trigger.
- 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.
- 15 April 2013If a permanent’s activated ability is on the stack when that permanent is detained, the ability will be unaffected.