Instinct: Spring into action when a victim comes close and slows their movement.
The venus fly trap is a black plant that ensnares its victims with its vines and pulls them into its pink jaws. The creature has secondary sets of jaws beneath the main ones which allows it to eat several meals at once. The roots of the Venus Fly Trap run deep, even under the face of a cracked rock wall or under flagstones, by the time you know you’ve encountered one the vicious tendrils are already moving behind you.
Edit: I’m trying to think of more plant themed dungeon obstacles. Deadly roots and spiked shoots, undead vines and mouldy slimes
Terrifying, isn’t it? You can test to push against the grain, but you risk injury.
Even some of those pitcher plants could spice up an otherwise bog standard pitfall trap. You’re in a hole, the sides are waxy and hard to scale, the top is lined with barbs, and if you spend too long at the bottom it starts to digest you. Or it coats you in a poison that intoxicates you, making it harder to climb out.