Poodle in the microwave. It's definitely a comedy.
I think Tate is a lot older than we think. He's not a
Frankenbaby, he's the
Frankenbaby, assembled from the original parts kept in jars for decades and reassembled by grieving Constance after the original Tate kills himself/is murdered by a lynch mob/goes to the electric chair (the option I like best, even if it assumes an unrealistically speedy justice system).
When the young lovers finally get around to doing the deed, Tate takes off his clothes and Violet notices the stitch marks...