Or, actually, HE swears. And I totally believe him.
When he's trying to be sneaky and he's busted doing something naughty, he will close his eyes and stand very still. When you say, "Kegan, I can see you..." he keeps his eyes closed and waves his hand back and forth in front of his face, just to make sure he's still invisible.
When you tell him, "Sorry, dude... still see you!" (which, yeah... I do. Because I love messing with him) he puts his hands over his eyes, making doubly sure that he's not only invisible, he's like Super Invisible, with a unitard and a cape and batcave. (And a sidekick. Which would be, sadly, me.)
When you say (and yes, by "you" I mean "when I say" because this is what I actually do say, every time) "Hmmmm... where did Kegan go? He was just here!" he keeps his hands over his closed eyes and walks backwards towards his original forbidden destination.
It's an act that kills, people.
It's too awesome to not work. Kegan's Cloak of Invisibility is a mad skill. You have to reward that kind of talent.
And by "you", once again, I totally mean me.
I can still see you, Kegan!!!!