Extremely ill/dead monarch chrysalid

[Megathymus ursus]

Hello,

A monarch larva I reared from ova near my home in Southern California grew fat and happy and pupated normally, but the final two or so days of its pupal life became a nightmare.

First, the "Oe blotches" of black that often appear in limited amounts along the wing and leg cases simply "blew up" almost before my eyes in the course of one day. The entire pupa became blotchy and almost entirely black. Parts of the abdomen around the black became yellowish. Finally, the entire chrysalid started turning chalky white in the tiny areas the black hadn't reached, and eventually this enveloped the entire pupa too.

When I was sure it was dead, I cut it open and found the entire pupa was dessicated and hollowed out; the dried remnants of tissues were tightly nestled against the interior walls.

What the heck was wrong with it? Was this a super-strong strain of Oe, something else, or a combination of diseases? I disinfected the egg and its first plant with bleach. Why did this happen?