A blood bulb is a turnip-like plant creature with a long thin needle at its root terminus rather roots. The leaves are likewise specialized acting as helicopter blades from the axial stem atop the bulb. They grow in colonies of two to eight, though there can be several colonies in the area, particularly along a path, riverbank or coastline.
When warm-blooded creatures pass within 15 feet of a blood bulb colony they entire group shoots up into the sky via their helicopter leaves. After zeroing in on their prey from above by sensing their relative warmth to the environment, they drop from the sky, impaling their victims. Blood bulbs then inject a sedative into their prey and then use their needles to draw in their victim’s blood until they are sated. A recently fed blood bulb can expand as large as an average-sized pumpkin, which gives one an idea of how much blood a single bulb can drain.