Lumpy white globs washing up on the shores of Canada’s Atlantic island province of Newfoundland have captivated the imagination of locals and baffled scientists for weeks.

The slimy, spongy globs, as big as dinner plates, were discovered by beachcombers in early September, scattered over the pebbly beaches of Placentia Bay on the island’s southern tip.

Several people posted pictures on social media, asking if anyone knew anything about them. Responses flooded in, with some speculating they might be clumps of cheese, alien feces, or whale boogers.

Others suggested they could be discarded breakfast biscuit dough or paraffin wax from a tanker that was cleaned out and discharged at sea. Some even attempted to light them on fire, discovering that they are indeed combustible.

Authorities say they are taking this possible pollution threat to the coastal environment “very seriously.”

The Canadian Coast Guard sent a three-person team to assess the situation and collect samples of the globs on the beaches west of the provincial capital, St. John’s, for testing.

Federal environmental emergency officers have also visited the area several times, conducting what the environment ministry described as extensive “aerial, underwater, and manual surveys of the beaches and shorelines to determine the extent of the contamination, what it is, and its potential source.”

“At this time, neither the substance nor its source has been identified,” Environment and Climate Change Canada (ECCC) spokesperson Eleni Armenakis told Agence France-Presse.

“Preliminary analysis at an ECCC laboratory suggests the material could be plant-based,” she said.

Further analysis of the “mysterious substance” is needed to determine exactly what it is and its potential impact, she added.