Mistwell
Crusty Old Meatwad
There is no RAW for it, but have fun with house rules. This is actually a pretty popular house rule from what I've seen.
RAW: That gargantuan dragon you just slaughtered is not considered difficult terrain nor cover.
I disagree.
RAW says "If you want to use something not covered in this chapter, refer to the examples here as a guideline...look at the sample terrain, find the closest match, and use those rules."
Closest match to a dead body looks to be ""uneven ground", which counts as difficult terrain.
I'd say RAW covers this situation, and calls it difficult terrain.