Cheapest priced copy (Commander Legends: Battle for Baldur's Gate): $1.99 at Card Kingdom, near mint, their price list as of .
Sewer Nemesis 
Creature — Horror · */* · Rare · The List · #CM2-75
As this creature enters, choose a player.
Sewer Nemesis's power and toughness are each equal to the number of cards in the chosen player's graveyard.
Whenever the chosen player casts a spell, that player mills a card.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
4 printings · $1.99 to $2.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Legends: Battle for Baldur's Gate | 771 | Rare | $1.99 | — |
| Commander Anthology Volume II | 75 | Rare | $1.99Out of stock | — |
| Commander 2011 | 98 | Rare | $2.49 | — |
| The List | CM2-75 | Rare | $1.99 | — |
One ruling from Wizards of the Coast
- 22 September 2011If the chosen player leaves the game, Sewer Nemesis's power and toughness each become 0. Unless another effect is raising its toughness above 0, it will be put into its owner's graveyard as a state-based action.