Soulsborne dragon bosses are usually a nightmare. You're partly fighting a giant blubbering mess of limbs that breathes fire, but you're mostly fighting the camera as it juts around while the dragon refuses to stay in your line of sight. Cue Placidusax, Elden Ring's two-headed dragon who's locked in a limbo cell outside of time. They're pretty tough, to say the least.
Notoriously difficult, a pain to reach, and nestled in a gigantic arena with plenty of space to slap you silly, Placidusax is up there as one of Elden Ring's toughest. But one player beat them on NG+3 with their own attack in one shot while naked, putting us all to shame. They did die while doing it, but it's an impressive feat all the same.
They rush up, cast Golden Vow, Howl of Shabriri, drink a Flask of Wondrous Phystick, stab themselves for a damage buff, then, when the fight begins proper, they cast Ancient Dragon's Lightning Strike, ripping Placidusax's health to shreds. However, while they were left vulnerable and unable to move during the cast, Placidusax's own Ancient Dragon's Lightning Strike cut them down as well.
Another key part of taking the Dragonlord (does two head make it lords?) down is using the Jellyfish Shield which you can find at the Foot of the Four Belfires Site of Grace. It ups your damage by 20 percent, which Fish_Smell_Bad (the original poster) said "gives a better damage buff" than the Gravel Stone Seal that some suggested.
Even if you do manage to replicate this build, there is one hiccup - RNG. The lightning strike may not hit enough times to take Placidusax out in one shot, so it's down to where you stand and where Placidusax stays. Get it just right and enough bolts will hit from one cast, leaving them completely dead. Hopefully, you won't join them.
As for why Fish_Smell_Bad is naked, I've no idea. Style?