A better translation of the Danish is actually "You wouldn't dare!" or as a dare in itself: "haha, i bet you don't have the guts to do it."
If you want to say "Don't you dare!" you might say "Du kan lige vove (at gøre det)!" or "Du kan lige prøve (på det)!" which basically mean "Just you try it!" Just as in English the intention of that is as a warning even though it's technically phrased as a dare.