Cheapest priced copy (Ixalan): $0.35 at Card Kingdom, near mint, their price list as of .
Ravenous Daggertooth 
Creature — Dinosaur · 3/2 · Common · Ixalan · #202
Enrage — Whenever this creature is dealt damage, you gain 2 life.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ixalan | 202 | Common | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 29 September 2017If your life total is brought to 0 or less at the same time that Ravenous Daggertooth is dealt damage, you lose the game before its enrage ability resolves.
- 19 January 2018If multiple sources deal damage to a creature with an enrage ability at the same time, most likely because multiple creatures blocked that creature, the enrage ability triggers only once.
- 19 January 2018If lethal damage is dealt to a creature with an enrage ability, that ability triggers. The creature with that enrage ability leaves the battlefield before that ability resolves, so it won’t be affected by the resolving ability.