So-called "zombie spiders" have been discovered in a cave between Co Cavan and Co Fermanagh.
They were found by speleologist Tim Fogg in the White Father's Cave.
Speaking on RTÉ’s Morning Ireland, Mr Fogg explained that common cave spiders become "zombies" after they are infected by fungi.
The fungus forces spiders to come out of the crevices in the walls and it then kills them, spreads its spores and infects more spiders.
"The fungus kills them and then their spores come out, and because they're out on the walls, the spores get blown about in the draft and therefore reinfect other spiders," Mr Fogg said.
He said the fungi have no nervous system or brain but can manipulate the behaviour of the spiders with chemicals.
Mr Fogg said the discovery of the fungi should be celebrated.
"Samples of this fungi, have now been stored for medical research because all sorts of things are coming out from fungi into medical research that are helping us with various diseases, including cancer," he said.
He said the species of fungi hasn't been found anywhere else but he is confident that more samples of it could be found in Ireland.
"We've looked over Sligo and Cavan and Leitrim, and we found examples in most of those. I'm sure if we look harder, we can find them around other places," Mr Fogg added.
