During a morning walk on an Australian beach, Brett Wallensky discovered a massive heap of sea creatures he described as “the stuff nightmares are made of.”

“There must have been thousands of them beached and they were all alive and wriggling,” Wallensky told Caters News. “The color of them was just amazing, it is so bright—almost alien.”

Lying in rock pools were thousands of venomous bluebottle jellyfish that had washed ashore at Barlings Beach in New South Wales on Friday, as was also reported in The Sydney Morning Herald.

The bluebottles, known outside of Australia as Portuguese man o’ war, feature long tentacles that can deliver a sharp sting. “It was the stuff nightmares are made of,” Wallensky …