Conversation so far:
Who was the Golden Age character, Joker?
Joker of Earth-Two is commonly referred to as the Golden Age Joker, thus being the main Joker that appeared throughout the Golden Age of Comic Books.
What happened with the character Joker in the Golden Age?
During the Golden Age, the first changes in the Joker began to appear, portraying him more as a prankster than threat.
Around what year was the character Joker's Golden Age?
The Golden Age for thr joker was roughly from 1940 to 1942
What significance did the character Joker have in the Golden Age?
The character Joker's regular appearances quickly defined him as the archenemy of the Dynamic Duo Batman and Robin; he killed dozens of people, and even derailed a train.

Question: What types of things did he do during this age?
Self-contained rewrite: What types of things did the character Joker do during the Golden Age?