I couldn't miss the chance to practice my drawing!
There are two at the start of the battle; killing them allows the Carniflower to open. If they reappear the flower will attempt to close and should be dealt with immediately.
In terms of attacks there are only two: a bite that reaches moderate distance and a tunneling attack. If characters are too close, they can be thrown into the poison thorn pit when they resurface. Freezing them with Blizzard is always a good idea.