These were the planet killers aboard the Hyperion.
The Vervoids are a carniverous plant killers. They were first in plant pods in the hyperderemics section. They were released when the worker who took Mel to the section electricuted the whole area and opened up the plants. There were six Vervoids in total but they were all released. They were wondering abput the vents and hiding inside the vents. They kept killing the crew and the passengers with these sharp poisonous needles.
The Vervoids are made of plants all over and had pink faces. The Vervoids nearly killed the entire crew and passengers. After a traitor among them ran off he was then captured and killed. The Vervoids were trying to get to Earth and make it a new Vervoid world. The Doctor managed to find a way to kill the Vervois. Him and Mel headed into the vents and saw all the dead people. They saw the Vervoids and then used their bombs. The Vervoids then rotted and dried out. All that was left was some dead leaves. The Doctor committed genocide by wiping out all of the Vervoids.
The Vervoids appeared in:
Season 23: The Trial of a Time Lord - Terror of the Vervoids