Cheapest priced copy (Fifth Edition): $0.35 at Card Kingdom, near mint, their price list as of .
Primordial Ooze 
Creature — Ooze · 1/1 · Uncommon · Fifth Edition · #261
This creature attacks each combat if able.
At the beginning of your upkeep, put a +1/+1 counter on this creature. Then you may pay {X}, where X is the number of +1/+1 counters on it. If you don't, tap this creature and it deals X damage to you.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
4 printings · $0.35 to $1.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Fifth Edition | 261 | Uncommon | $0.35 | — |
| Chronicles Foreign Black Border | 54 | Uncommon | — | — |
| Chronicles | 54 | Uncommon | $0.35 | — |
| Legends | 160 | Uncommon | $1.79 | — |
One ruling from Wizards of the Coast
- 4 October 2004It becomes tapped even if the damage is prevented.