The picture looked more like Nuclear polyhedrosis virus (NPV):http://www.evansonart.com/monarchdisease.html
"Nuclear polyhedrosis virus (NPV): caterpillars and chrysalises are affected. According to Monarch Watch, this is the pathogen that affects monarchs the most. Signs: larva may hang limply by prolegs and
die, larva grows restless and is prone to climbing high before death, larva becomes brown (photo C9) before death, and chrysalis fills with brown fluid or has brown spots (C4-5) and will shrivel."
I would go ahead and freeze this in a doubled baggie and then toss it out after 24 hours. The butterfly may still be alive. I hate to throw them away in the trash when there still could be life. This is probably not OE.