Earth Eater

Earth Eater grants the Pokemon complete immunity to Ground-type moves. Instead of taking damage, the Pokemon heals 1/4 of its maximum HP whenever it is hit by a Ground-type attack. This absorption applies to all damaging Ground moves, including Earthquake, Earth Power, and Bulldoze.

The ability converts what would be a damaging attack into a free healing opportunity, making the Pokemon an excellent switch-in against Ground-type attackers. Status Ground moves like Sand Attack are also unaffected. The healing occurs regardless of whether the move would have been super effective, neutral, or resisted.

Earth Eater is the signature ability of Orthworm, the Steel-type Pokemon introduced in Generation IX. For a pure Steel-type, Ground immunity is exceptionally valuable since Ground is one of Steel's three weaknesses. This converts a normally threatening matchup into an advantageous one, effectively removing one of Orthworm's key vulnerabilities while providing sustain.