Cheapest priced copy (The List): $0.35 at Card Kingdom, near mint, their price list as of .
Overgrown Armasaur 
Creature — Dinosaur · 4/4 · Common · Rivals of Ixalan · #141
Enrage — Whenever this creature is dealt damage, create a 1/1 green Saproling creature token.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The List | RIX-141 | Common | $0.35 | — |
| Rivals of Ixalan | 141 | Common | $0.35 | $0.79 |
2 rulings from Wizards of the Coast
- 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.
- 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.