Question

Where should the dash or dashes be placed?

Answer 1

the second one

Cats are loveable and—hey, stop eating my plant, you bad cat!

Answer 2

Cats are lovable and—hey, stop eating my plant, you bad cat!

This is because the speaker is being cut off, which in this case is what the dash should be placed, the speaker is obviously being knocked off course from their sentence, stopping abruptly.