Lobster aren't sea roaches, these are:
I've seen thousands of them on the Georgia coast, and can usually be found when the tide washes out from jetties and rock formations along the sea. They climb the rocks and frequent the pools of water at the base of the rocks where I believe they lay their eggs. They're nice creatures, actually, and will let you pick them up, as my young Daughter found out. Not nearly as nasty as a real roach.
But, they're called sea roaches.https://en.wikipedia.org/wiki/Ligia_oceanica