When I'm in high school you'll be dead!

So I'm watching you last Saturday since your mom went out. While I'm giving you a bath you asked me, "How old are you uncle?" I said that I was 40 years older than you so if you're five then I'm 45. If you're six then I'm 46. So later while we are lying in bed getting ready to put you to sleep you say, "I'm five and you're 45." "When I'm six you'll be 46." "When I'm in high school you'll be dead!"

I was laughing so hard then I said, "Uncle is sad you said that. Why did you say that?" And you said, "My brain just thinks it and I say it!"