Admiral Holdo’s hyperspace-kamikaze in The Last Jedi. I mean, why hasn’t anyone used this in any space battle before, ever?
Because they couldn’t afford to lose large cruisers like that before and also a damn lightsabre didn’t just split in two erupting a huge flash of force energy at the exact same time. Why do you think the explosion trails were pure white? 😉
To be fair it tore a wing off of the Supremacy and took down other ships in the way