Cheapest priced copy (Commander 2016): $7.49 at Card Kingdom, near mint, their price list as of .
Kalonian Hydra 
Creature — Hydra · 0/0 · Mythic · Magic 2014 · #181
Trample
This creature enters with four +1/+1 counters on it.
Whenever this creature attacks, double the number of +1/+1 counters on each creature you control.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
7 printings · $7.49 to $59.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Bloomburrow Commander | 226 | Mythic | $7.99 | — |
| Commander 2016 | 154 | Mythic | $7.49 | — |
| Commander Anthology Volume II | 140 | Mythic | $7.49Out of stock | — |
| Magic 2014 | 181 | Mythic | $8.99 | $59.99 |
| March of the Machine Commander | 305 | Mythic | $7.49 | — |
| 30th Anniversary Play Promos | 21 | Mythic | — | $20.99 |
| The List | M14-181 | Mythic | $7.99 | — |
One ruling from Wizards of the Coast
- 1 July 2013To double the number of +1/+1 counters on a creature, determine how many +1/+1 counters are on the creature and put that many more on it. Effects that interact with counters (such as the one created by Corpsejack Menace's ability) may change the number of counters ultimately put on the creature.