"There is no room for demons, when you're already self-possessed" - Carrie Fisher -- RecklessPrudence
The demon Az'bar'bijol, once summoned, launched itself at the luckless human who was foolish enough to read its incantation out loud. And almost got the spiritual equivalent of a concussion when it was repelled by a possessing force already in residence, so to speak.
"Nice try," said the human. "But you can't do that with me. And... soon as I whip up a binding spell, you won't be free to do mischief in the mortal realm either."
"What?" said the demon Az'bar'bijol. "How?" It looked around. The human had made a perfect summoning circle and made certain that it could not exit through any crack. And it was ringed about with sea salt. "Why?"