It'll all end in sick and tears. One of Mrs INJ's favourites, but originally from her mother - generally about a film or TV programme.

......s! I've shot 'em (one of my father's when he came across any particularly shoddy piece of work or poor service; as in 'Cooks! I've shot 'em'.

You won't die! (mother, in response to a variety of mild childhood traumas). OK so far.

I'll go and jump in the clock! - apparently a favourite from my late paternal grandmother, and, no, my Dad doesn't know what she was getting at either

... and one for aunt Aggie. My mother adding spoons of tea to the pot, though I don't remember any aunt with that name.

Pull my finger!   Thanks Dad!

Quis!, my dad would should with his hands behind his back. The first son (of 3) to shout "Ego!" would get the treat - chocolate, sweets etc.

Keep that. Come in 'andy even if you never use it. (Work colleague/technician/jack of all trades).

Arsenal!
my dad, whenever anyone sneezed, in tribute to Eric 'n' Ernie

What a der-brain! (Sung to the tune of the Hallelujah chorus)
My dad again, prior to contemporary theories on raisinf kids' self-esteem

[Projoy] Well if we're bringing out child abuse, I used to get called "You silly, twisted boy" (a Grytpype-Thynne line, I believe) by my dad, and my mum's go-to threat to make me behave was "I'll bash your face in", which I've discovered works on my own children (the empty threat, that is) :-)