Correction appended, March 7, 2017

A turtle in Thailand needed surgery after it ate more than 900 coins that humans had thrown into its pool for good luck.

The 25-year-old female green sea turtle known as Bank is recovering after undergoing an operation Monday to remove the coins, which had merged into an 11-pound ball in her stomach and became life-threatening, according to the Associated Press.

The animal lived seaside near the eastern town of Sri Racha, where many superstitious visitors seeking luck and long life throw coins into the water, the AP reports.

“I felt angry that humans, whether or not they meant to do it or if they did it without thinking, had caused harm to this turtle,” Nantarika Chansue, who led the surgery, told the AP.

Correction: The original version of this story misstated the location of the turtle. The coins were thrown in its pool, not in the sea.

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