"Do you like thorns~?" She made another cut on the neck and gathered more blood on the scalp-brush. In her other hand she suddenly had a small bag of seeds. "This'll be a bitch for anyone who tries to come in our room without permission."
As she 'painted' the edge of the door, she sprinkled the seeds onto the wet blood. Then she waved her hand over those seeds and they sprouted into life, tendrils of roots plunging into the wall while thick green leaves and thorns crawled up the sides, following Emerald's movements.