>>79047561>>79047597The size is the result of Luffy inflating his bones.
The coloration is an ability that pretty much everybody who's worth anything in the second half of the series has called "Armament Will". A fighter's willpower turning into an armor over their bodies. There's two other forms (It's called 'haki' in moonspeak) that enhance your senses, or let you impose your will on others so hard that those weaker than you just pass right the fuck out.
Let's them strike past defenses, including the broken as fuck element powers called "Logia"
It doesn't count as the 'super sayian' equivalent because, again, everyone who's a front line fighter in the series now has it.
Even the wimpiest member of the crew, Usopp, has a form of it that lets him see beyond regular human sight.
https://www.youtube.com/watch?v=LyyG9DXuBDM 
