This article is about a member of House Heterodyne. For others in the lineage or other uses, see Heterodyne (disambiguation).

Egregious Heterodyne is one of the Old Heterodynes, and thus one of Agatha's ruthless ancestors. He destroyed the first Castle Heterodyne, built on the site of the spring that was the family's power source. Having concluded the spring was too small he decided, like a true spark, to increase its flow in the most egregiously destructive manner possible , with massive consequences for everybody around. The result was the destruction of the original castle and the creation of the River Dyne. He considered this a success.