
I'm WARNING you.
I was judo champion at math camp.
The Big Bang Theory Season 1, Episode 15

Mr. Wolowitz,
this is your second WARNING.
The Big Bang Theory Season 1, Episode 13

Just a WARNING, Sheldon.
The freezer locks from the outside.
The Big Bang Theory Season 2, Episode 23

Computer:
Warning.
Primary containment breach.
Westworld Season 2, Episode 10

You'll see it at work.
Just a WARNING:
The Big Bang Theory Season 12, Episode 6