Cheapest priced copy (The List): $0.49 at Card Kingdom, near mint, their price list as of .
Witch Engine 
Creature — Horror · 4/4 · Rare · The List · #USG-169
Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
{T}: Add {B}{B}{B}{B}. Target opponent gains control of this creature. (Activate only as an instant.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.49 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The List | USG-169 | Rare | $0.49 | — |
| Urza's Saga | 169 | Rare | $0.99 | — |
One ruling from Wizards of the Coast
- 1 April 2008Because the ability is targeted, it is not a mana ability. It can only be activated when you have priority, and goes on the stack like other non-mana abilities.