it's simple just
Swadloon evolves by happiness.
happens when is it happy
swadloon evolves into leavanny when you level it up with high friendship
Evolve Swadloon, to do that you just have to battle with it alot.
Level 20 it evolves to Swadloon
Swadloon Evolves by Happiness
Sewaddle evolves into Swadloon, which evolves into Leavanny.
sewaddle evolve when you level them up to lv 20 they evolve into swadloon
with happiness at 220
Swadloon is a Grass and Bug type pokemon.
the 74th episode of black and white BW074 OR 731st of the whole anime
Sewaddle becomes level 20 -----> Swadloon gets a level up while holding a Soothe Bell -----> Leavanny is final form