- Egon Spengler: There's something very important I forgot to tell you.
- Peter Venkman: What?
- Egon Spengler: Don't cross the streams.
- Peter Venkman: Why?
- Egon Spengler: It would be bad.
- Peter Venkman: I'm fuzzy on the whole 'good/bad' thing, what do you mean bad?
- Egon Spengler: Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.
- Ray Stantz: Total protonic reversal.
- Peter Venkman: All right, that's bad. Ok, all right, important safety tip, thanks Egon.