I’m not kidding.

It’s not quite little green men, but Russian cosmonauts have found microscopic organisms living on the outside surface of the International Space Station.

The microscopic lifeforms, identified as a type of sea plankton, were found during a spacewalk recently.

“Results of the experiment are absolutely unique,” Russian ISS Orbital Mission Chief Vladimir Solovyev told ITAR-TASS. “This should be studied further.”

Phytoplankton similar to what was found on the surface of the ISS

Phytoplankton similar to what was found on the surface of the ISS

Gizmodo reports that there’s a chance that this life not only survived in the vacuum of space, but it might have multiplied and grew!

Neither NASA nor the Russian space agency can account for how sea plankton ended up on the outer hull of the ISS. One far-fetched explanation says that atmospheric currents might be lifting the lifeforms up from the ocean all the way to the ISS — which is 205 miles in the sky.

The lifeforms were found when cosmonauts on a clean-up mission analyzed engine gunk that had dirtied the surface of the ISS.