Butterfree

Butterfree is a Bug/Flying-type Pokémon introduced in Generation I. In Super Smash Flash 2, Butterfree appears as a background character in the stage, Saffron City.

Pokémon description
Butterfree is an insect-like Pokémon appearing as a large butterfly. Butterfree has a large purple body with light blue limbs and a nose with very small fangs. Its eyes are quite large in proportion to its head and are a red color. Butterfree's large wings simply appear as black and white butterfly wings. The gender difference is the female has purple on the bottom of its wings and the male does not.

In Super Smash Flash 2
A male Butterfree appears as a background character of Saffron City, along with Moltres. It will occasionally fly through the sky in the distance from right to left, and it has no effect on the match.