Panagrolaimus detritophagus is a terrestrial free-living nematode (roundworm).

[3] In 2018, it, along with another nematode species (Plectus parvus) became the first multicellular organism to be thawed back into a living state after prolonged cryopreservation.

[4][5] Pleistocene permafrost was obtained from the Kolyma River lowland, and thawed.

It decomposes soil organic matter with the aid of symbiotic bacteria.

They multiply quickly after an organic enrichment event, and then their population rapidly declines when nutrients run out.