These miniatures are from the now discontinued Runewars game. I assembled them a while ago and rebased them onto round bases for D&D, then ended up getting distracted by other projects. After Brushchewer did such a good job on my Terrain Crate stuff, these were sitting on a shelf looking sad and unpainted when I was looking around for the next job for her to do - and she's knocked it out of the park.
I let her pick her own paint scheme on these ones, and I'm really happy with this grimy, threatening look she's gone for rather than something brighter and cheerier.
These could easily be used as evil Treants or Tree Blights in D&D. There's a lot of flexibility to them, too - they could be a magical experiment gone awry, evil magic blighting the land, or animated by some evil wizard or druid. With quite a few different "large killer plant" stat blocks in D&D at different levels, there's some solid options at different party levels to pick from.