A Myna is a bird character who appears in the episode "A Myna Problem".
In the episode's story, Clumsy was out with Puppy in the forest playing when Puppy comes across an injured Myna bird. Clumsy and Puppy decide to take it to the Smurf Village to take care of it until it gets better. Brainy gets jealous of the attention the Myna gets and decides to be its caretaker. However, the myna has a big problem insulting the other Smurfs, and later, Papa Smurf says the Myna is better now and it should go back into the forest.
Later, Scruple finds Gargamel's spell book and the Myna overhears the spell he says. The Myna accidentally turns the Smurfs into ducks. In the end, the duckling Smurfs escape Gargamel's bag that he put them in and soon, they end up reverting back to normal with the help of Papa Smurf. The Myna comes back in the end and says one last goodbye before going back into the forest.