Marill

Marill is a mouse Pokemon from the Johto region. It was one of a few Pokemon from Generation II to make an appearance before the debut of the Johto Journeys, the first Pokemon series to introduce new Pokemon that aren't part of the first 150 roster (151 if you count Mew).

Marill was once identified as a pure Water type Pokemon until Generation VI when its type was changed into a dual Water/Fairy type.