What is the name for someone who obsessively exercises slight power? [duplicate]

"Give a man a hammer, and everything he sees will be a nail," is an astute observation of human behavior. What is the name for someone with slight power, for example, the power to vote to close a question on this site, who exercises that power obsessively and gleefully?

Solution 1:

power happy

Example:

Watch out, @abc has almost reached 50K rep. I can just see it now, he's going to be power happy, running about closing everything he can get his hands on.

(Not based on any real person I've ever seen here.)

Solution 2:

In British English we have the noun jobsworth which the Collins online dictionary defines as

a person in a position of minor authority who invokes the letter of the law in order to avoid any action requiring initiative, cooperation, etc

The word derives from the sentence "That's more than my job's worth" which is popularly supposed to be petty officials' response to non-standard requests. The definition does not quite match the request but in practice someone being deliberately obstructive or pedantically officious is often referred to as "a jobsworth"