This plant uses its tentacle-like vines to strangle it's prey, not unlike a snake.
In escaping the Devil's Snare, expose some light upon the plant. It will shrivel and recoil from the light. Casing any lumos spell, or even shining a torch, will cause the Snare to release you.
Harry, Ron and Hermoine fighting the plant. "Devil's Snare, Devil's Snare. It's deadly fun, but will sulk in the Sun." (Image by thepolestar. Devil's Snare is the creation of J.K. Rowling).
