This is where things get weird. The Dark bead knocks me into the floor. Like the Zwei R2, but for pathetic damage (for 1/4 of my hp).
Now, I've PVPed all this while inductively concluding that knockdowns granted invulnerability (i.e DSlayer arrow knockdowns give invincibility, BS knockdowns give invincibility, Zwei/demon greataxe knockdowns give invincibility) but he instantly followed up with another R1 dark bead and it took off most of the rest of my hp while I was on the ground. This second dark bead also resetted me into a standing 'stun' animation.
Following this I rolled out behind him, and he dark beaded the empty space in front of him where I'd been 2 seconds prior, instantly lagshot killing me as I recovered from the roll behind him. I had 9 poise.
I'm confused about a few things.
1) Do knockdown animations (as in, where your character ends up falling to the floor) always offer invincibility frames?
2) If not, what weapon/spell knockdowns cause knockdown with no invinciframes?
3) Is it normal that a parry must be executed before 2 consecutive spear R1s to work? Watching Jblackmel I've always thought that you needed to parry as the first hit struck, but it seems you actually have to parry earlier than that to parry the second hit.