Cheapest priced copy (Lorwyn Eclipsed Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Hapatra, Vizier of Poisons 
Legendary Creature — Human Cleric · 2/2 · Rare · Amonkhet · #199
Whenever Hapatra deals combat damage to a player, you may put a -1/-1 counter on target creature.
Whenever you put one or more -1/-1 counters on a creature, create a 1/1 green Snake creature token with deathtouch.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $0.49 to $16.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Amonkhet | 199 | Rare | $0.69 | $5.99 |
| Lorwyn Eclipsed Commander | 123 | Rare | $0.49 | — |
| Amonkhet Promos | 199s | Rare | — | $16.99 |
2 rulings from Wizards of the Coast
- 18 April 2017If you put enough -1/-1 counters on Hapatra so that its toughness is 0 or less, its last ability triggers.
- 18 April 2017If you put any number of -1/-1 counters on more than one creature at once, Hapatra's last ability triggers once for each of those creatures.