Beach-goers beware.

Millions of jellyfish are washing up on the shores of beaches in Washington and Oregon, CNN reports.

It is not unusual for the bluish-purple species called Velella velalla to turn up in the spring, but a sail fin on their body usually keeps them away from the shore. This spring, though, their sails were no match for the wind.

The species, also known as “purple sailor,” has stinging cells that are not seriously harmful to humans, but the Oregon State website warns it’s best to avoid rubbing your eyes after touching them or walking barefoot through them on the beach.

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