Doopler
The Dooplers were a humanoid species known for involuntarily duplicating themselves (termed "dooplercating") as a defense mechanism against uncomfortable emotions such as embarrassment. As the act of dooplercating was itself regarded as highly embarrassing, a single duplication could easily trigger a multiplicative chain reaction that results in an exponentially increasing number of duplicates. However, once the Doopler regained control of themselves, their duplicates would automatically merge back into one (termed "de-dooplercating").

In 2381, the  transported a Doopler emissary to Starbase 25 for trade negotiations. When they arrived at the starbase, Captain Carol Freeman inadvertently caused the emissary to dooplercate; the situation quickly snowballed out of control, with the duplicates overwhelming a large portion of the Cerritoss saucer section. Eventually, Freeman realized that angering the duplicates with insults would cause them to regain control and recombine. Later, she deliberately set up the emissary to dooplercate again at the Command Conference afterparty. ()

One of the Doopler duplicates was trapped beneath the Cerritos hydroponics bay and not merged with the others. Its skeletal remains were still there as of 2382. ()
Species