MArcomage

The image for this should be, ideally, a metallic gauntlet flying through hallways apparently by its own power, with a red numbered counter in feet or meters on its knuckles, and a black hemisphere on its back.
I don't expect anyone to find or draw such a picture, but it gives you an idea of what a 'good enough' sort of picture would be.

Edit: Also, the fact it isn't unliving isn't a typo; it doesn't seem right for golem messenger to be summoning it.

This thing?

Nope; there's even bands and songs and things with just "sheer heart attack"-- the most context you're ever going to get is from searching for the entire "Sheer Heart Attack, the Bomb Hand".

I did, which is what brought me to JoJo's Bizarre Adventure.

https://www.google.com/search?q=%22Sheer+Heart+Attack%2C+the+Bomb+Hand%22&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=rcs

Two pages on my end. (Even though it still hilariously gives a huge number of search results at start.)

Ah, I see. I was looking at image search results and reading the pages that appeared most relevant. But aside from its use in JJBA, its sources are all text-based.