Cheapest priced copy (Eldritch Moon): $0.35 at Card Kingdom, near mint, their price list as of .
Mournwillow 
Creature — Plant Skeleton · 3/2 · Uncommon · Eldritch Moon · #187
Haste
Delirium — When this creature enters, if there are four or more card types among cards in your graveyard, creatures with power 2 or less can't block this turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Eldritch Moon | 187 | Uncommon | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 13 July 2016Because the last ability’s effect doesn’t change the characteristics of any permanents, the set of creatures affected is constantly updated. Any creature with power 2 or less at the moment blockers are chosen will be unable to block.