I recently used some Thorns (from MM2, I believe) that I thought worked out pretty well. They all had different plant traits, and resembled a specific kind of plant - one of them was made of rose vines (Rosewhip), another was mostly poison ivy, and another was made of nettles. It worked well for when I needed some warrior-fey, and the PCs did underestimate them quite a bit. They were allies for a while, until one of the PCs killed the one they had been traveling with, since he had a hatred of fey.
That ended up getting him killed.