the.com/spider crab

means A long-legged, often spiny-shelled marine crab (family Majidae and relatives) with a small body and gangly, spider-like limbs, found crawling slowly across the seafloor.

from Straightforward compound coinage — 'spider' plus 'crab' — naming the creature by resemblance rather than lineage: those disproportionately long, thin legs radiating from a small central body read as spider-like to anyone who's seen one skitter across a tide pool. 'Crab' itself traces back through Old English 'crabba,' related to Old Norse 'krabbi,' both likely echoing the animal's scrabbling, crawling motion. No hidden backstory here — the name is just honest, if slightly unflattering, physical description.