Smizmar is a term taken from the Amphibiosan language. A smizmar is similar to to a spouse or mate, with a minor difference. When an Amphibiosan feels love for another person, their bodies enter a "receptive" state. In this state, their skin becomes a semi-permeable membrane which allows the passage of genetic material. In this state, they can be impregnated by anyone they come into physical contact with. The contributor of the genetic material is often the smizmar, since the loving couple will usually have much intimate contact, but it is not necessarily the case. In fact, direct contact is not even required, and individuals have been known to be impregnated by public toilets. In Amphibian culture, the smizmar is viewed as the true parent of the offspring, regardless of who provided the genetic material.
This complex relationship can create insteresting drama, and was seen in the episode Kif Gets Knocked Up a Notch, as well as in the feature film "When a Man Loves a Smizmar."