Dick and the Other Guy 3rd Rock from the Sun : Season 3 Episode 23

An eccentric new professor has arrived at Pendleton University and Dick is quick to befriend him; he soon becomes annoyed when Dr. Neesam appears to be able to do everything better than he can, and becomes a rival for Mary's affections. Sally becomes concerned that Officer Don has lost interest in her after hearing a woman tell him he was "great last night", so Mrs. Dubcek convinces her to disguise herself and follow him around.