Conversation with Oob

We are driving to a 2:00 appointment

Oob (cheerily): It's 2:00!

Me (Panic!  Look at the clock!): No, it's only 1:45, honey.

Oob (undaunted): It's 2:00!  It says so on my invisible watch.
(shows me his wrist on which no watch is visible)

Me (long pause): If it's invisible, how can you see what time it is?

Oob (wiggling his eyebrows): X-Ray Vision!