I’ve noticed whenever my cats go into bat-shit-crazy mode, their pupils are the size of silver dollars. Even though they are in a brightly lit room.
I’m just curious if that’s intentional or what?
Pic
I doubt it. What would be the advantage?
Human pupils change in size under certain situations not related to light as well. I don’t know why it happens, but it does, and it’s not subject to conscious control. Cats undoubtedly have the same situation.
Cats don’t teach. They don’t need to teach. They have slaves.
Whut? 
Disclaimer: Slave to five cherubs.
No it’s an involuntary response to adrenalin among other things. Human pupils will react similarly under stress ( excitement, fear ).
ETA: Think back on times you’ve heard somebody described as “wide-eyed with excitement.” Those dilated pupils are what helps make those eyes look wide.
I’ve been a free man (catless, that is) for a number of years, but I clearly remember the many times my gray shorthair would be sitting, loaf-of-bread, utterly placid… and then suddenly her eyes would dilate to demon-black and she’d go, as you put it, batshit crazy.
So whatever it is, the “attack” precedes the batshitness. It doesn’t follow the crazies, in other words.
Yeah, it’s part of mammals’ fight-or-flight response from our “sympathetic” autonomic nervous system. I guess the theory is that it allows us to take in more information, even in brightly-lit situations, but it’s at the cost of losing some focus.