dicephalia
Dicephalia is a term used in biology to describe organisms that have two heads. This condition is relatively rare in the animal kingdom and is often associated with parasitic relationships. The most well-known example of dicephalia is the tapeworm, a type of flatworm that can develop a second head when it infects a host. The second head, known as a scolex, is used for attachment and absorption of nutrients from the host's digestive system. In some cases, dicephalia can also occur in other invertebrates, such as certain species of annelids and mollusks, where it may result from asexual reproduction or other biological processes. The presence of two heads in these organisms can have significant implications for their behavior, reproduction, and survival strategies.