Creature - Imp {T}: Choose target non-Wall creature the active player has controlled continuously since the beginning of the turn. That creature attacks this turn if able. If it doesn't, destroy it at end of turn. Play this ability only during an opponent's turn, before attackers are declared.1
If the Imp leaves play before the end of the turn, the creature still is destroyed. [D'Angelo 1995/04/12]
The ability may only be used on a creature on its controller's turn at a time when it would be legal for that player to declare an attack later in the turn. [Aahz 1995/04/11]
The creature is destroyed if it does not attack because it simply cannot do so legally. For example, a Sea Serpent will be destroyed if it cannot attack because the opponent has no islands. [Aahz 1994/06/01]
You can use this effect on a creature you know won't be able to attack. For example, you can use it on a tapped creature. [Aahz 1994/06/01]
Extended tournaments (see Rule 803) have banned this card since 1999/10/01.
Seconda Edizione
(Uncommon)