On holidays in Spain a few years ago, I spotted "caracoles de mar" on a menu. The name translates literally as "sea snails" - they look bit like a whelk with 1 cm. spikes all over them. Sort of a punk-whelk. Taste fine - was it a "romesco" sauce?

What was interesting was that in the English version of the menu, they were described as "shrimps"! Bet that caused a few surprised expressions when brought to table...

Regards