Spontaneous generation Puns

Characters: My wife, my son (four years old), and my daughter (his twin, so obviously also four).

Son: "My classmate didn't like me laughing at her today."

Wife: "Why were you laughing at her?"

Son: "I'm a vampire! Bwa ha ha ha ha!"

Wife: "OH! Like an evil laugh?"

Son: "Yeah! Bwa ha ha ha ha!"

Daughter: "I'm a witch! Hee hee hee hee!"

Wife: "So you're both monsters?"

Son: "Yep!"

Daughter: "Hee hee hee hee!"

Wife: "Am I a monster too?"

Son: "Yeah! You're a ... " <dramatic pause> " ... mummy."

Whole family in hysterical laughter, and after it dies down he goes, "Get it!? Mummy!"

I've never been so proud. A spontaneously generated pun of that caliber at four years old, AND an unnecessary clarification/repetition of the joke? I've got high hopes for this one.