Larkspur

"What? You think you can run from me? What an idiot you are.."
Larkspur is a threatening flower monster of unknown origin. It manifested in a forest and chases out any humans who try to enter.

Appearance
Larkspur is an exceptionally large flower-like being. The estimated height being of an average tree.

She posesses five red petals. She has no facial features beside a mouth.

Personality
When not bothered by anything, Larkspur is concentrated on her surroundings, almost as if she's looking for trouble.

Larkspur is sadistic and violent in most encounters with intruders, not skipping a beat to attack them if they refuse to disappear.

Larkspur is stubborn, especially regarding her power and abilities, and she'd probably do anything to get even stronger.

She usually feels no empathy, either.

Towards Lavender she isn't quiet about her sinister thoughts, however she obviously doesn't act as revolting.

Bullet Pellets
Larkspur can summon a nearly endless amount of pellets which she can launch. Yes these are essentially the same thing as Flowey's friendliness pellets.

Solar Laser
A charged attack. Larkspur culminates solar light in her petals. By closing them and jerking her head forward she can launch a laser beam.

Roots
She can let her roots emerge from the ground and use them as spikes or arms to grab things.

Digging
Since her lack of legs, she transports herself by descending into the ground and digging towards a direction to emerge elsewhere. While underground she can neither attack nor be attacked.

Fusion
Though she rarely does, with mutual consent she can fuse into one entity with Lavender, creating Columbine.

Trivia

 * Her headcanon voice is Flowey from the Undertale Musical
 * big surprise i know
 * Larkspur is diurnal (day-active) and rests during the night.