Andromeda (dog)

Andromeda is Susan Evers's pet dog in The Parent Trap.

When "Susan" returned from camp, Andromeda was the only one who realized that she wasn't the real Susan and barked at her.

Trivia

 * Andromeda's fate was never revealed in the three sequels. However, being a dog, she would've passed away in the 25 years between The Parent Trap and The Parent Trap II.