Dummy Digicore
From Wikimon
The Dummy Digicore 「ダミー･デジコア Damī Dejikoa」 is an item that appears in Digimon Collectors. It is developed by Agumon Hakase and Nise Agumon Hakase, during the game's final event, as a weapon for the Tamers to defeat Death-X-mon. It could be obtained in-game through the special quest "Dummy Digicore Development".