Cheapest priced copy (Dark Ascension): $0.35 at Card Kingdom, near mint, their price list as of .
Soul Seizer // Ghastly Haunting 
Creature — Spirit // Enchantment — Aura · 1/3 · Uncommon · Dark Ascension · #50
Flying
When this creature deals combat damage to a player, you may transform it. If you do, attach it to target creature that player controls.
Enchant creature
You control enchanted creature.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dark Ascension | 50 | Uncommon | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 22 January 2011If Soul Seizer leaves the battlefield in response to its triggered ability, you won't be able to transform it and it won't return to the battlefield or become attached to the target.
- 22 January 2011You choose the target for Soul Seizer's triggered ability when that ability triggers and goes on the stack. You choose whether or not to transform it when that ability resolves. If the creature is an illegal target by that time, the ability doesn't resolve and none of its effects happen. You can't have Soul Seizer transform.
- 22 January 2011If Soul Seizer has any +1/+1 counters on it when it transforms, they remain on Ghastly Haunting. They won't affect the power or toughness of the enchanted creature, however.