Alevita

Alevita was a planet that existed far from Earth. It had an incredibly thick atmosphere, causing all its life to have very potent pheromones and the tendancy to burrow and anchor into anything it can.

The smaller creatures plants all determined the mammals of their planet were a threat, and so evolved to be able to change their pigments and deter the animals, eventually causing all mammals to go extinct. The remaining creatures and plants all lived in an acknowledged harmony that they'll continue on Earth

Unfortunately, a nearby planet's moon had been flung outside it's normal gravitational pull and smashed into Alevita, causing the planet to be nearly destroyed.

A few meteors, carrying life from Alevita flew to Earth, with its creatures burrowing as deep as they could to survive the impact.

The ecology of Alevita has a few parallels with Earth, mainly in the aesthetics of the creatures. Smaller creatures like bugs and insects and also reptiles and plants evolved to have the most complex social systems on the planet, though still quite rudementary compared to earth's humans.

They manage to change the colour of certain aspects of their hosts, like eyes, as due to their evolution of pigment changing.