Cheapest priced copy (Mystery Booster 2): $6.99 at Card Kingdom, near mint, their price list as of .
Oath of Druids 
Enchantment · Rare · Exodus · #115
At the beginning of each player's upkeep, that player chooses target player who controls more creatures than they do and is their opponent. The first player may reveal cards from the top of their library until they reveal a creature card. If the first player does, that player puts that card onto the battlefield and all other cards revealed this way into their graveyard.
Legal inCommanderVintage
Banned inLegacy
Not legal inBrawlStandardPioneerModernPauper
4 printings · $6.99 to $279.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2016 | 159 | Rare | $10.99 | — |
| Exodus | 115 | Rare | $42.99 | — |
| Judge Gift Cards 2001 | 2 | Rare | — | $279.99 |
| Mystery Booster 2 | 212 | Mythic | $6.99 | $39.99 |
2 rulings from Wizards of the Coast
- 1 October 2009The targeted player controlling more creatures than the current player is a part of the targeting requirement. A player can't be targeted by this ability unless it's true, and the ability doesn't resolve if it's no longer true at that time.
- 1 October 2009The ability can only target an opponent of the current player.