Goblin Mountaineer

Evasion at the cleanest possible rate: one red mana buys a small body whose entire pitch is that it walks straight past anyone keeping Mountains in play. The design is older than the Goblin tribal archetype that would later make tiny red creatures matter, and it shows in how naked the package is: no haste, no tribal payoff, no second ability, just a creature and a keyword that turns the mirror's own land choices into a liability. Mountainwalk is the most parochial of the landwalk variants because it only bites when the defending player controls a Mountain, so the card is built around a specific wager about what the defending player's manabase looks like rather than a universal evasion clause like flying or fear. That conditional is the whole story. Against the right board it is an unblockable chip-damage engine that costs almost nothing to deploy; against anyone with no Mountain in play it is a vanilla creature that trades down to a coin flip. The Portal-era pedigree matters too: this was a card designed to teach the landwalk rule to new players in plain terms, the kind of straightforward, single-purpose creature the introductory products leaned on before the main sets started layering keywords onto Goblins. This is the unalloyed version of an idea later red cards would dress up with relevance: evasion you only get to keep if your read on the opponent is correct.