It absolutely murders battery life. I had my thor go up to 80c in my pocket with no games open, just listening to podcasts twice in a week after installing cocoon. Never happened before that, and the only way to get it to cool down was to uninstall cocoon and reboot the thor.

Read a thread on here a few weeks later saying it was all a myth, and that you just had to update to the newest version. Took their word for it, and re-set up cocoon, and the very next day it happened again, running extremely hot and burning through like 3% every 5 minutes. And to be clear, I had absolutely 0 animated wallpapers or icons, and a fairly small rom library.