Gonna put the TL;DR here:
The POB: https://pastebin.com/L7zVzRiZ
The YT Showcase: https://www.youtube.com/watch?v=-ScCX3_xc6Y

About the build:

• Elem vs Necro is mostly personal preference. Necro is probably better at the top end since it scales with minion damage and your defenses are mostly block which has several good abilities linked with it whereas the Elem build is scaling mostly via golem buffs and stripping resistances.
• Build still has a fairly good amount of upgrading that can be done, which is nice.
• The build scales insanely hard with cast speed. Get as much of it as you can.
• Spectres are Stoneskin Flayer and Lithomancer, both of which are obtained from primal ruins in delve. If you can't get those, use Auto-Enforcer and Guard Captain which are both obtained in Heist, Auto-Enforcer from tunnels/repository and Guard Captain from mansion/records office.
• Build is currently on standard because I'm done with ultimatum and wanted to re-do one o fmy favorite builds as elementalist now instead of the former necro that it was.

But...Why?
Because I wanted to screw with 2 of my friends by making the most visually obnoxious build I could. Lots of tinkering and brainstorming lead me to the conclusion that rapidly triggered detonate deads would be far and away the best skill to accomplish that task. After a while it turned out that the build was legitimately good and I eventually took it to my first 100 and invested quite heavily into it.