Topic: "Bonk" sound effect

[MrHaroldG2000]

In the Stooges shorts, a whip was used as the sound effect for a slap, a kettledrum for a punch to the stomach, and a tearing of the cloth for hair - usually Larry's - being pulled out. What was used as the sound effect for a bonk on the head (or the knocking of heads together)?

[FineBari3]

It was probably a low pitched wood block.  (Percussionist here....)