You may be looking for the plant, Cowslip
Cowslip was a minor antagonist in Watership Down but the part he played gave an extra adventure to the story. He was a member of the Warren of Snares, and although seems to have some authority, he claims that his warren has no Chief. He is a large rabbit, who is used to good food and safe surroundings. He becomes soft with odd behaviors like the rest of his warren. He was the first to approach Hazel and his group, keeping a deadly secret and refusing to answer questions. When Bigwig gets caught in a snare, Cowslip refuses his assistance and punished Fiver for even talking about it. It becomes obvious that Cowslip has kept their domestication a secret and allowed the Sandelford rabbits to fall victim to the daily snares so that he had that much longer to live. He traded good food and safety for the ways of wild rabbits and freedom from fear.
Captian Holly, Bluebell, and Pimpernel, traveled to Cowslip's warren, looking for Hazel, Fiver, and Bigwig and Cowslip immediately ordered that they be attacked and killed. He and his rabbits attacked, killing Pimpernel and wounding Holly. Holly fought back, planning on killing one of them because of Pimpernel and easily won against the soft Cowslip. To save his own life, Cowslip admitted that Hazel, Fiver, and Bigwig were on the Down. Holly left the cowardly Cowslip with a scratch. In the book his appearance was described as 'princely'. His people were also described as such, all looking similar. They all were orange, and they had smooth fur. Most are rather large, yet they aren't good fighters, because they are fed and protected (and destroyed) by man.
Cowslip is the Chief Rabbit of the Warren of the Shining Wires, convinced that the local man takes care of the warren and doesn't want the freedom Hazel and his Owsla have, even convinced to the point that El-ahrairah is nothing but a lie. There is some doubt as to whether he is insane or totally evil. Hazel, Fiver and Bigwig first encounter him when they accompany Captain Holly to recover an injured Sandleford rabbit left there, only to learn the warren's terrible secret when Bigwig nearly becomes a victim and that the missing rabbit was a victim. He becomes angered by Hazel's warren when they help a group of his rabbits escape from his warren, and even helps Woundwort to get his revenge on them. However, as he himself states, "I'm a plotter, not a fighter" and he uses both sides for his own gain.
- Cowslip is voiced by Denholm Elliott in the film and Stephen Fry in the series.