Colloquially known as the "weeds of space", the Reptos hungered for both scavenged metal and scavenged flesh. Their victims were placed in regenerative states within flesh-hives and used as spare parts until their bodies were too far gone to be useful. They were known to be some of the most ruthless scavengers in the universe.
When the Entropy Cloud began to consume Microspace however, their planet was one of the first to be consumed, wiping out Repto society.
After the Micronauts entered the Cloud, the Heliopolis came under attack by the Reptos. The creatures began cutting in the hull and the Micronauts divided their numbers to better deal with them. The sheer number of Reptos however proved too much and Oz gave Microtron the order to shut off the reality synchs and let the Heliopolis implode to kill the beasts. A Time Traveller suddenly materialized and aged the Reptos to dust.