What did my hen lay?

[YHWHreigns]

My son went to gather eggs this morning and found this disgusting looking egg. He said my red link just came out of the nesting box. My daughter poked the placenta looking thing and yolk came out... Is it something I should worry about? She seems fine, but I have never seen anything like this before. Anyone else have any answers?

 

[paddock36]

 

[dawg53]

Here's a link for you to read through with pics:
https://www.backyardchickens.com/t/976010/please-identify-this-alien-entity-found-in-coop