What is the Laboratory short clip of Dexter telling Dee not to run with scissors from Cartoon Network?

You're likely thinking of a popular internet meme, but there's no official "Laboratory" clip with Dexter telling Dee "not to run with scissors."

The phrase "Don't run with scissors" is a common safety warning, often used in a humorous context. It's possible you've seen a fan-made video or animation using characters from Dexter's Laboratory or that the phrase was used in a comedic way in a different episode or series.

If you can provide more context about where you might have seen this, I might be able to assist further!