What is this?

Ice pick. Patented by William F. Arndt and John H. Ganzer as US Patent No. 2,070,773 on Feb. 16, 1937.

"This invention relates to ice picks and it has for its object to provide a simple and convenient device for removing ice cubes which have been formed on a cake of ice and disposing of them as desired."

That's an ice chipper! It's seems Coolerator refrigerators weren't cold enough to actually freeze ice but you could order a big block of ice and it would hold for awhile in the fridge. That tool is part of the process of getting ice cubes from the block. Collectors Weekly describes how the tool is used. For more context, this Youtube video shows the whole process of getting ice cubes from an ice block, but uses a slightly different Coolerator tool to break up the cubes.

A 2016 PDD post goes into more detail about Coolerator refrigerators.

This led me to a fascinating search for the true history of Coolerators. They were still powered by a big block of ice at least until the 1940s, as shown by this ad from the Duluth Herald from May of 1940. This is a great example of how terminology changed (or didn't change) in fairly recent history. There are still people alive who remember the ice man delivering ice for their ice box, which was also called a refrigerator, but didn't have coolant. And "making ice" meant chipping off from the big block. There's likely another post on the way.
 

Note in the ad above, it says they only ice their Coolerator every 4-7 days. That means a big block of ice was delivered from the Duluth ice and fuel company, which was promoting the use of these devices that needed ice. Little did they know, someday the need for purchasing ice would be gone.