A Syncytia is a cell with more than one nucleus.
They are found in humans in the case of sicknesses like RSV, HIV, etc. Mitosis is NOT two nuclei - the nuclear envelope disappears during mitosis so the DNA is no longer in a nucleus!
Some cells in the human body normally have more than one nucleus but this is kinda rare - liver cells, urinary system cells, parietal cells (of the stomach), chondrocytes, heart muscle cells can have more than one.
Hope this may helps u............