Was I just having a lucky day or has the new update buffed rare monster spawns?
In 1 Mission through the Scarlett Fortress:
http://steamcommunity.com/profiles/76561198054716117/screenshot/50463941...
http://steamcommunity.com/profiles/76561198054716117/screenshot/50463941...
http://steamcommunity.com/profiles/76561198054716117/screenshot/50463941...
I've seen other people ask questions like this in the past, but I had never actually found a mewkat in-game until today. I've also seen very little of the rock jellies, but now I found more than 5 today.
The only legitimate rare monster spawn was the Mewkat.
Rock Jellies always spawn in Grim Gallery. It isn't a rare spawn unless it's disguised as a stone block.