Heartseeker
Artifact — Equipment
Equipped creature gets +2/+1 and has "
, Unattach Heartseeker: Destroy target creature."
Equip 
(: Attach to target creature you control. Equip only as a sorcery. This card enters unattached and stays on the battlefield if the creature leaves.)
Michael Sutfin
Darksteel (DST)
• #124Rulings
“Unattach Heartseeker” means just that — Heartseeker moves off the creature it was equipping and remains on the battlefield.
(wotc • 2004-12-01)
Heartseeker grants an ability to the equipped creature. The ability can target a creature with protection from artifacts (unless the equipped creature is an artifact creature).
(wotc • 2004-12-01)
The equipped creature’s controller chooses whether or not to activate the activated ability. It doesn’t matter who controls Heartseeker.
(wotc • 2004-12-01)
Rulings
“Unattach Heartseeker” means just that — Heartseeker moves off the creature it was equipping and remains on the battlefield.
(wotc • 2004-12-01)
Heartseeker grants an ability to the equipped creature. The ability can target a creature with protection from artifacts (unless the equipped creature is an artifact creature).
(wotc • 2004-12-01)
The equipped creature’s controller chooses whether or not to activate the activated ability. It doesn’t matter who controls Heartseeker.
(wotc • 2004-12-01)