The Jahns are members of an alien race from the moon that invaded Vinny's Tomodachi Life playthrough. They originally arrived on Vineland Island as a set of 3 identical individuals, except for one Jahn which had a helmet; this one became known as Captain Jahn. Vinny wanted to experiment with the individuality of the three Jahns, focusing on whether or not they chose different favorite foods. However, they soon began enacting their plan to take over the island through assimilation of the other miis. The assimilated miis would mysteriously disappear, and their apartments would suddenly be inhabited by new Jahns.
The invasion was thwarted off-stream, shortly after the arrival of agents Mulder and Scully on Vineland Island. Only one Jahn remained. This Jahn had supposedly renounced his assimilative ways and wished to live as the other miis did. To fit into regular society, he changed his wardrobe and assumed the identity "Lumber Jahn." He also experimented with drugs in an attempt to better integrate.
- The name "Jahn" is derived from the speech patterns of an old college pal of Vinny's and Mike's. According to Vinny, this man addressed everyone as "Jahn."
- Lumber Jahn's greeting ("Slow it down") is also something this friend used to say.
- Vinny has conjectured on-stream that the Jahns were brought to Vineland Island by Vinesnauce "Vlinny" PastaPizza.