Butterfly or moth larva (11)
I believe the answer is:
caterpillar
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">butterfly or moth larva</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 caterpillar that I've seen before include "crawler" , "looper, perhaps" , "Heavy tracked earth-moving vehicle" , "Moth/ butterfly larva" , "future monarch, perhaps" .)