Eight-limbed mollusc (7)
I believe the answer is:
octopus
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">eight-limbed mollusc</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for octopus that I've seen before include "Tentacled marine mollusc" , "army swimmer" , "Cops out (anag.)" , "Invertebrate sea creature with three hearts" , "person with widespread influence" .)