Cheapest priced copy (Foundations Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Whiptongue Hydra 
Creature — Lizard Hydra · 4/4 · Rare · Foundations Commander · #240
Reach
When this creature enters, destroy all creatures with flying. Put a +1/+1 counter on this creature for each creature destroyed this way.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $0.49 to $0.69 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2018 | 36 | Rare | $0.69 | — |
| Foundations Commander | 240 | Rare | $0.49 | — |
| Neon Dynasty Commander | 134 | Rare | $0.49 | — |
2 rulings from Wizards of the Coast
- 13 July 2018If a creature with flying would be destroyed, but an Aura with the umbra armor ability is destroyed instead, Whiptongue Hydra won't count that creature or that Aura as a "creature destroyed this way."
- 13 July 2018A creature with indestructible or a creature that regenerates won't count as having been "destroyed this way."