BTW, this afternoon, I was running the Roomba. It was vacuuming the dining room, which is where Captain likes to curl up in front of one of the heating registers.
I was in the living room, so I didn't see exactly what happened. However, I suspect that the Roomba must have either run into Captain or made him THINK it was about to run into him. Either way, suddenly I saw an orange blur speeding out of the dining room, through the entire length of the living room and then halfway up the steps to the second floor. (The cats figured out long ago that jumping onto the furniture or up a few steps on the stairs gives them a good vantage point to spy on the Roomba from above, and that it can't climb up after them.)
Not long afterward, I had reason to go to the second floor. Captain followed me up and complained to me the entire time. What makes this noteworthy is that he wasn't making his normal "Mrrrrp" vocalization; he was telling me his tale of woe with full-fledged "Meow! Mew! Meowww!" utterances, a sound he rarely makes. I presumed he was telling me all about the mean old Roomba and how it scared him.
Silly kitty. That'll teach him to sleep on the floor next to the heating register when the Roomba is running.