Had a co-worker who would rarely join weekly team meetings, but any time he did he would immediately jump in with "I hate to derail this meeting but..." followed by a question to the team that would of course derail the meeting.
I finally got fed up as I was leading the meetings (and he was technically above me in the company), so I responded with "You know- that's a good and pretty involved question that is worthy of its own meeting. I'm going to proceed with the published agenda, but feel free to schedule a separate meeting with the relevant members of this team to cover your topic."
After a couple of times of that, he stopped interrupting the meetings but he never scheduled those other meetings either.