Si and Am

They are villains from Lady and the Tramp and Lady and The Tramp II: Scamp's Adventure.

Si and Am played Flotsam and Jetsam in The Little Mer-Maddision Marples-Macintosh
She is a eel

Si and Am played Kaa in The United State Book (2016) (disneystyle172 Style)
They were an female snake