Story highlights The purple sailor jellyfish has a sail fin that usually keeps it away from land

But westerly winds have overpowered them by the droves onto Pacific beaches

(CNN) Otherworldly goo lumps in blue and purple speckled beaches in Oregon and Washington states this week, after strong wind got caught in their sails.

Millions of jellyfish are washing up on shore, leaving beachgoers watching their steps. Except for at least one child, who couldn't resist putting a shoe on them.

"They were really goopy and mushy and they were weird to step on," Brooke Brandweide of Seattle told CNN affiliate KOMO

These bluish, purple jellyfish, called Velella velella, sometimes invade in spring, though their body design usually keeps them out of sight, by allowing them to sail away from shore.

"They have a sail fin that has a slight bend to it and that helps them curve again from the beach and stay off the beaches," said Steve Green with the Coastal Interpretive Center in Ocean Shores, Washington.

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