It's worth noting that the version of Eclipse of RUIN is the result of Sun (who was on Safe Mode, which seems connected to Dreadbear) and Moon, who was controlled by Glitchtrap, merging back into one. Not to mention Eclipse's endo baring a strong resemblance to the Mimic. (+)

The fact that the Old Man is the one who gives Jeremy Glitchtrap's code also makes sense, since Glitchtrap came from the Mimic.