Cheapest priced copy (Battle for Zendikar): $0.99 at Card Kingdom, near mint, their price list as of .
Undergrowth Champion 
Creature — Elemental · 2/2 · Mythic · Battle for Zendikar · #197
If damage would be dealt to this creature while it has a +1/+1 counter on it, prevent that damage and remove a +1/+1 counter from this creature.
Landfall — Whenever a land you control enters, put a +1/+1 counter on this creature.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $0.99 to $9.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Battle for Zendikar | 197 | Mythic | $0.99 | $2.99 |
| Foundations Jumpstart | 736 | Mythic | $1.29 | — |
| Battle for Zendikar Promos | 197s | Mythic | — | $9.49 |
5 rulings from Wizards of the Coast
- 25 August 2015If damage that can't be prevented is dealt to Undergrowth Champion while it has a +1/+1 counter on it, you'll still remove a +1/+1 counter on it.
- 25 August 2015If Undergrowth Champion is dealt damage from multiple sources at the same time (for example, if it's blocked by multiple creatures), its prevention effect will apply once to all that damage. You'll remove only one +1/+1 counter.
- 8 November 2024A landfall ability triggers whenever a land you control enters for any reason. It triggers whenever you play a land, as well as whenever a spell or ability puts a land onto the battlefield under your control.
- 8 November 2024Whenever a land you control enters, each landfall ability of the permanents you control will trigger. You can put them on the stack in any order. The last ability you put on the stack will be the first one to resolve (As a result, you can have those abilities resolve in the order of your choosing.).
- 8 November 2024A landfall ability doesn't trigger if a permanent already on the battlefield becomes a land.