Psyduck evolves into Golduck at level 33. It second evolution grants the Pokémon significant increases in almost all of its base stats. Golduck is Psyduck's only evolution.
While both Psyduck and Golduck have access to psychic type moves, it's important to note that it is still considered a water-type Pokémon only, and keeps this single type in both stages of its evolution. It has the ability to stop explosion- and self-destruct-type moves with its innate ability "damp." It can also cancel out weather-type effects that buff the stats of opposing Pokémon through its innate ability "Cloud Nine." Golduck and Psyduck both see their speed stats doubled under rainy weather.