Cheapest priced copy (Darksteel): $0.79 at Card Kingdom, near mint, their price list as of .
Surestrike Trident 
Artifact — Equipment · Uncommon · Darksteel · #147
Equipped creature has first strike and "{T}, Unattach Surestrike Trident: This creature deals damage equal to its power to target player or planeswalker."
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.79 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Darksteel | 147 | Uncommon | $0.79 | $3.99 |
3 rulings from Wizards of the Coast
- 1 December 2004“Unattach Surestrike Trident” means just that — Surestrike Trident moves off the creature it was equipping and remains on the battlefield.
- 1 December 2004Surestrike Trident grants an ability to the equipped creature.
- 1 December 2004The equipped creature’s controller chooses whether or not to activate the activated ability. It doesn’t matter who controls Surestrike Trident.