Cheapest priced copy (The List): $0.35 at Card Kingdom, near mint, their price list as of .
Frilled Deathspitter 
Creature — Dinosaur · 3/2 · Common · Rivals of Ixalan · #104
Enrage — Whenever this creature is dealt damage, it deals 2 damage to target opponent or planeswalker.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The List | RIX-104 | Common | $0.35 | — |
| Rivals of Ixalan | 104 | Common | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 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 your life total is brought to 0 or less at the same time that Frilled Deathspitter is dealt damage, you lose the game before its enrage ability resolves.
- 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.