From wikipedia “Konrad von Hochstaden at the tower of Cologne City Hall standing atop an autofellatio-performing grotesque.”

I didn’t do much research on it, but supposedly no one quite knows who did this or why.

Archbishop of Cologne (1238 – 1261), von Hochstaden wielded great influence in imperial affairs but was a controversial and contentious figure. Ultimately, to generate funds for continuing work on the cathedral, he initiated a tax on hops (thus raising the price of beer), a move that may have influenced the grotesque ornamentation added by stone carvers at the base of his statue.

He also was supposedly always fighting with the people of cologne and using “unscrupulous” methods. He plotted to kill the king, and sold his vote for the new king for a high price. Sounds like he did plenty to earn the privilege.

Supposedly the tower it appears on was largely destroyed by allied bombing, and rebuilt... I wonder wether this was recarved, or even present on the original? It might be interesting to research further.