Quote Originally Posted by Qwertystop View Post
Similarly, any caster who doesn't have to use an implement or ritual for preparing spells or getting slots back, and who has lots of Silent Still spells.
Actually... take a 20th lvl wizard with a Silent, Still Polymorph prepared. Said wizard gets killed, knocked to -10HP. By RAW, there's nothing preventing him from taking non-physical actions, so he burns that MM'd Polymorph to change into something with a nice, high Constitution. Immediately he gains back HP as if he had rested for the night, and then gains bonus temporary HP based on his new Con score, putting him back into the postives (potentially even from far lower HP totals, especially with MM-cheese and higher level polymorph effects).

I like it!