Cheapest priced copy (Stronghold): $0.99 at Card Kingdom, near mint, their price list as of .
Crovax the Cursed 
Legendary Creature — Vampire Noble · 0/0 · Rare · Stronghold · #55
Crovax enters with four +1/+1 counters on it.
At the beginning of your upkeep, you may sacrifice a creature. If you do, put a +1/+1 counter on Crovax. If you don't, remove a +1/+1 counter from Crovax.
{B}: Crovax gains flying until end of turn.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Stronghold | 55 | Rare | $0.99 | — |
3 rulings from Wizards of the Coast
- 4 October 2004You can only sacrifice one creature to it each turn.
- 4 October 2004Crovax can sacrifice itself to its upkeep triggered ability.
- 4 October 2004If you choose not to sacrifice a creature and he has no +1/+1 counters, then nothing bad happens. Note that some other effect must be keeping him alive if he has no counters.