"Half-Breeds on Venus" is a science fiction short story by American writer Isaac Asimov.

As Max is getting on in years, he gives his elder son Arthur the task of preparing the underground settlement where the Tweenies will live, keeping out of sight of the planet's human settlers.

Several months later, the Tweenies are busy setting up their new underground town below a nearby ridge when a group of human settlers crosses over from the far side of the mountains.

Accompanied by a group of Phibs, Henry and Irene travel for three days to the Venusian lowlands.

There, the Phibs use their telepathic abilities to take control of three large, dangerous twenty-legged reptilian carnivores called Centosaurs.

Then the Centosaurs break free of the Phibs' control and try to attack them, but Henry and Irene are able to fend them off with their Tonite ray guns until more Tweenies arrive to finish them off.