Cheapest priced copy (Duel Decks: Venser vs. Koth): $0.99 at Card Kingdom, near mint, their price list as of .
Aether Membrane 
Creature — Wall · 0/5 · Uncommon · Planar Chaos · #93
Defender; reach (This creature can block creatures with flying.)
Whenever this creature blocks a creature, return that creature to its owner's hand at end of combat.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.99 to $4.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duel Decks: Venser vs. Koth | 48 | Uncommon | $0.99 | — |
| Planar Chaos | 93 | Uncommon | $0.99 | $4.49 |
One ruling from Wizards of the Coast
- 1 February 2007The blocked creature is returned to its owner’s hand at end of combat only if the blocked creature is still on the battlefield. It doesn’t matter whether Aether Membrane is on the battlefield.