I like #3 because of the concept, but it also makes me want something more like a burrowing anglerfish. Basically I'd just prefer it to pop out and fight instead of just open the ground/facehole and bite you. Either way its a good way to incorporate a droppable ingredient
#8 I picture hiding like a flower up in tree leaves and attacking anyone who tries to chop that tree down, and then flying down at your head like a facehugger... which would be awesome.
I know this is supposed to be more for look than behaviour, I just have a hard time judging one without picturing the other.