“A guy walks into a bar...” is a typical form of what has been called the “bar joke.” A chemistry version is:

“An acid and a base walk into a bar. The police later arrested the two for a salt.”

The joke was posted on Reddit—Jokes on September 10, 2017. “So an Acid and Base walk into a bar.Gets a bit wet and salty from that moment onwards” had been posted on Twitter on August 20, 2013.


SimHQ Forums
Re: A neutrino walks into a bar [Re: semmern]
Sauron
#3499677 - 01/20/12 09:53 PM
(...)
An acid and a base walk into a bar together.

“What the hell?” says the bartender. “This is the first time I’ve ever seen an acid and a base walk into this joint together in all the years I’ve been keeping bar here! I never thought I’d live to see the day!”

The acid turns to the base and says, “You see? I told you the two of us together was going to produce some sort of a reaction!”

Twitter
Ira Alif Syabil‏
@liverpool_98
So an Acid and Base walk into a bar.Gets a bit wet and salty from that moment onwards
10:22 AM - 20 Aug 2013

Reddit—Jokes
An acid and a base walk into a bar
submitted September 10, 2017 by dawayoflife
The police later arrested the two for a salt.