Anubias are plants in the Aroid family (Araceae), which includes the popular Cryptocoryne in aquaria, Pistia (Water Lettuce) in tropical ponds, as well as Anthuriums, Philodendrons, Alocasia and many other genera. In a brightly lit tank they will sometimes flower underwater but will not set seed as far as I know. It would also take two flowers, and possibly two different clones. The "flower" consist of a spathe (a modified leaf) and a spadix (the rod shaped part). In Ariods the female flower parts are receptive before the male pollen is produced. This prevents self-pollenation thus requiring two flowers. Some Ariods will not set seed if both plants are from the same clone, and many Anubias are produced in tissue culture and are thus likely clonal if purchased from the same source.
Anubias often flower if grown above water in a greenhouse or terrarium, but I have never had any set seed by accident.
Many Aroids are easy to grow from fresh seed, the trick is producing seed!