"Meicoomon (Rookie)"

"Meicoomon (Rookie)" is an unnamed Rookie level Digimon.

Etymologies
No name available for this Digimon.

Development
This unnamed Digimon's first appearance was in the  smartphone service Shabette Concier as part of a promotional campaign for Digimon Adventure tri.. In this campaign and service, it was referred to only as the Mysterious Digimon (Child) (ナゾのデジモン(成長期)); although Meicoomon itself does not appear in the campaign at all, the URL to install this Digimon in Shabette Concier states this Digimon is Meicoomon's Rookie form.

In this campaign, users of Shabette Concier could download a free "Mysterious " virtual assistant, which hatched and digivolved as time passed. The Digi-Egg hatched into "Meicoomon (In-Training)" at some time between October 6 and November 10, 2015, and digivolved into this Digimon between then and March 6, 2016.

It was unknown whether the two Digimon were considered official until 2023, when the In-Training Digimon appeared in Digimon Ghost Game, "The Devourer of All" [67]. It was also unnamed in this appearance as well.