I think someone doesn't need speed when you're EVERYWHERE AND NOWHERE at the same time, no matter how fast Bill manages to ru- i mean, fl-... whatever, Giygas will be literally one.. """""step""""" further, While Bill as moving at god knows what speed, Giygas was already there, waiting for him to arrive
Not mentioning Giygas classic "You cannot grasp the true form of Giygas attack!" and "Giygas did SOMETHING!", these are things that may be so horrifing, or so powerful, nobody really knows what it is, but something is sure: it DOES hurt you, it DOES damage, and it's A LOT (i recall losing a lot against Giygas while playing, and i mean it)
The only thing that could save Bill for a horrible death, is if he somehow maanged to break the fourth wall and convince whoever is watching to help him defeat Giygas
The "You cannot grasp the true form of Giygas attack" is similar to Giegue "The form of Giegue attack was inexplicable!" By the way, it's outside help to ask someone to for help outta of the battle /:
In side note, Giygas attack is likely some PK/PSI attack that I guess cannot be perceived in a way, these include: PK Flash, PK Thunder, PK Freeze, PSI rocking (which is a wave attack by the way) and PK Fire. Also, Giygas ABSORBED Paula's call for help by the darkness.
Yes you're right, i forgot that (didn't battle Giegue in a LONG time honestly), still, there's no debout that those attacks do a lot of damage.
If Bill can't call for help to anyone (special the one out of the 4th wall) than is Game Over to him, he can't do anything, can't hit him, can't make deals, and God have mercy on him if he decides to enter Giygas' mind (if there's anything left of it that is)
"Giygas cannot think rationally any more, and he isn't even aware of what he is doing now. His own mind was destroyed by his incredible power. What an all-mighty idiot!"- Pokey Minch
It's clear that Bill can't enter in his mind, he can interact with Giygas, but that's just it. (don't quote me, it's gonna get too long.)