That is a phenomenal mini that deserves use, even if Heroscape isn't a game that really features doors outside of the Fortress Door (and man, if one of those could suddenly turn into a mouth and eat someone...
). As such it'd be a difficult mini for a Mimic design.
Other than that, they do seem to be pretty useful since they can give any Yokai/Construct a sudden Chomp threat to any adjacent figure as well as teleport them back to the Start Zone free-of-charge. 70 points a pop for a Common Hero is pretty pricey though so I'd be interested to hear how they playtest.
~TAF