Cheapest priced copy (Double Masters 2022): $0.35 at Card Kingdom, near mint, their price list as of .
Gnarlback Rhino 
Creature — Rhino · 4/4 · Uncommon · Foundations · #638
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever you cast a spell that targets this creature, draw a card.
Legal inCommanderBrawlStandardPioneerModernLegacyVintagePauper
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters 2022 | 148 | Common | $0.35 | $0.49 |
| Foundations | 638 | Uncommon | $0.35 | — |
| Core Set 2020 | 300 | Uncommon | $0.35 | — |
2 rulings from Wizards of the Coast
- 12 July 2019Gnarlback Rhino's last ability triggers when you cast a spell that has multiple targets as long as at least one of those targets is Gnarlback Rhino. It doesn't trigger multiple times if you cast a spell that targets Gnarlback Rhino multiple times.
- 12 July 2019Gnarlback Rhino's last ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered.