At Shatner Q&A and he was asked for a story about time on the Star Trek set, which started a story about him gaslighting De:
They filmed really late, and one shoot at 2 am, Deforest told Bill he’d been worried about his memory lately and thought he might be starting to lose it. Of course, Bill decides to fuck with him the next morning at breakfast.
De fixes himself a bagel (first mistake, cause Bill thinks it’s funny that he’s not eating grits cause he’s a ‘southern gentleman’) and after De presses it down in the toaster, Bill asks Leonard to go distract him. Leonard pulls De to the side, saying somethings in his eyes, and while they’re gone Bill steals the bagel out of the toaster, shoves it in his pocket, and puts the toaster back down. De comes back, waits in front of the toaster, and it pops up with nothing inside. De starts mumbling to himself, and gives up and fixes another bagel.
Bill sends Leonard to distract him again, but no longer has a pocket for this bagel and shoves it in his mouth to eat it. De comes back, toaster pops, no bagel. Then he starts to get pissed off, and he whips around in time to catch Bill furiously trying to eat his bagel in time, and shouts,
“YOUUU SON OF A BITCH!”