Prof Horne studies the fossil remains of ostracods to better understand winter and summer temperatures experienced by early humans in the British Isles.

But Emily Ellis, an evolutionary biologist who studies these displays, knows what they really are: blobs of bioluminescent mucus vomited up by crustaceans called ostracods.

Hardt says that male Ostracods "produce absolutely humongous sperm, ten times the size of the male himself."