Get's 
's Ult passive for 4 sec.
Current state of the game requires to ult and lose that tankiness in less than 4 secs before being useful anyway. Think about it.
[zombie-brand-mindblown]
Edit: This small comparison is merely to put in perspective my 
QQ cry to nerf the monstrosity aka 
Olaf's ult is a trade-off to provide some counter-play.
If Olaf was tanky, high damage, fast-moving, self-sustaining and could not be disabled... what would be the counter-play? by removing his bonus defenses, he is made at least somewhat vulnerable to focus fire in exchange for being a rampaging unstoppable force.
Graves is stupidly overpowered right now, nothing 5 movement speed, 50 damage shaved off of Q and Mana cost nerfs to said Q will fix
They need to tone down the amount of damage his bullets do and actually nerf the ratios on his Q.
