SOS Encounter: Poni Gauntlet (30%)
Its base catch rate is 45 out of 255 (higher is easier); the catch rate calculator works out your odds with each ball. For the look, the best colour match is Fast Ball, Repeat Ball or Level Ball.
Evolution: Dratini → Dragonair (Level 30) → Dragonite (Level 55).
Dragonite in every game · Pokémon Sun, Moon, Ultra Sun & Ultra Moon interactive map (Alola)