Abominable snowmen (5)
I believe the answer is:
yetis
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">abominable snowmen</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for yetis that I've seen before include "Beasts that aren't real" , "Abominable snowmen" , "Mountain monsters" , "More than one mythic creature" , "Mythical creatures" .)