Cosmo

Nobody knows where Cosmo came from. She eats rainbows and stardust, and hops planets like she's in a trampoline park. Cosmo can see the entire universe from her starry eye, and she can understand the language of every human and animal, making her a great friend to everyone.

Catching her is the tricky part. If Cosmo is not where you left her, she is on another planet, possibly in another universe, and she will be back when she is back.