Ivytail is a brown tabby she-cat.
In Twilight, Ivytail catches a strange sickness that doesn't seem as if it can be cured. The sickness is caused by the shiny Twoleg liquid spilled on RiverClan territory, and eventually leads to Ivytail's death due to the inability to have it cured. Another elder, Heavystep, catches the illness from her during her burial.
When Leafpool and Mothwing arrive in camp, Leafpool sees Heavystep and Hawkfrost carrying Ivytail's body out of camp. Leopardstar then announces her death to her Clan, and Mothwing's confidence plummets.
Leopardstar later mentions her death at a Gathering, explaining how she and a kit had died, but Leafpool had helped to prevent it from killing any other cats.