Toxoplasma gondii is a single-celled parasite that commonly infects cats but can infect other mammals and birds. Its life cycle involves sexual reproduction in the intestines of cats (definitive host) and asexual reproduction in warm-blooded animals (intermediate hosts). Yes, it forms tissue cysts, especially in the brain, muscle, and other tissues of warm-blooded hosts. The oocyst stage of the Toxoplasma gondii life cycle is seen in cats. It resides in the cat's intestines.