Screencapping GOTG2 it occurred to me, you know how Mantis always stands in the same position whenever Ego is around, her hands always clasped at the front like she’s terrified…
(bear in mind I’m not an expert in body language or anything…) She probably is terrified too, of course, she does the same thing when Ego’s not even there-
but also… she’s lived her whole life with only Ego for company, and both of them know her sleep-inducing powers are transmitted by touch. We the audience know she’s capable of knocking him out if she really tries, if she can touch him for long enough. What’s the odds that, at some point, he demanded of her that she always kept her hands where he could see them?