Aysheia

Aysheaia (or Aysheia) pedunculata was a soft-bodied, caterpillar-shaped organism average body length of 1-6 cm, first appearing in the Cambrian explosion.

In truth, it was one of several animals in an aquarium that a family of space travelers brought with them on their vacation to Earth. Despite the father's misgivings, he allowed his daughter to empty the aquarium into the oceans, thereby spurring an explosion of life.