Colossendeis colossea is a species of sea spider (class Pycnogonida) in the family Colossendeidae. The species was first described by Edmund B. Wilson in 1881. It is the largest pycnogonid species known to science, reaching a leg span of . Body length, including proboscis and abdomen, can reach .
Colossendeis colossea is a deep-water species inhabiting continental slopes at depths between m. It has a semi-cosmopolitan distribution in all main oceans apart from the Arctic Ocean.