Scientists have identified the massive carcass which mystified locals in Indonesia after washing up on a beach last week.

The nearly 15-metre-long carcass has been identified as a Baleen whale , according to Alexander Werth, a whale biologist at Hampden-Sydney College in Virginia.

“There is lots of stuff in the ocean that we don’t know about — but there’s nothing that big,” Werth told CBS News Monday. Tweet This

The question now becomes what specific kind of Baleen whale it is, and what the exact cause of death was. The latter question is key, as whale carcasses generally sink, becoming food for a wide variety of deep sea life.

Werth says two possible causes of death that would cause a Baleen whale to float to land are an internal baterical infection, which would produce large amounts of internal gas and a collision with a ship or vessel that resulted in an injury which prevented internal gasses from escaping.

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“That’s yet another reason you don’t want to be close to these things, not because it’s a scary, spooky creature, but [because] it would just be releasing some pretty foul, noxious gases,” Werth said.

The Jakarta Global reports that the carcass was discovered by local resident Asrul Tuanakota, 37, late Tuesday evening in Huamal Beach in West Seram District, Maluku.

Tuanakota says he initially mistook the 15-metre-long carcass for a boat in the darkness.

At the time, a spokesperson for Indonesia’s Ministry of Marine Affairs and Fisheries (KKP) told the Indonesia Tribune that they believe it to be some kind of whale.

“If we look in terms of physical almost the same as the whales,” Nasrul Latulanit of the KKP’s Office of Marine and Coastal Resources Management told the Tribune. “If the nature of squid is biggest only up to 5 metres, if the whale can be 20 to 30 metres.”