Considering how absolutely busted troll characters like Bugs Bunny, Roadrunner, The Mask (Loki) etc are, Akainu is actually being pretty smart lol.
Even if Luffy doesn't kill you, he'll humiliate you so hard now, he will ruin your reputation, willpower, self respect etc potentially lol.
Blackbeard if Luffy gets to use Gear 5th on him without BB nullifying it:
https://youtube.com/shorts/oIIqzSJuxp8?feature=share
I'm not sure if I'll recover seeing an Admiral get tooned by Gear 5th if it does happen. I bet Oda will be sadistic enough to do it eventually though lol.
I'm still trying to process Luffy tooning Kaido so hard and sending him to his apparent death in a volcano too.