This copper cudgel-scepter found in a late Yamna Kurgan is the likely prototype of the infamous Vajra of Indra Deva. It's a unique object, and the single largest metal object ever found in a Yamna grave. It weighs 750 gm & was likely used to crush or shatter the enemy.
Kutuluk Kurgan, with the Copper cudgel-scepter found by Kuznetsov clearly visible next to the skeleton of the Yamna man.
The fact that our ancestors used weapons of this kind is clear from the "bar-celts" found by Falk in the Copper Hoards deep in the Gangetic plains in 2nd millenium BCE. The Yamna cudgel is around 1000 years older than the Indian ones.