In that form he's just pure energy, Thrull can't smash him, and that's assuming he somehow hits him, or even gets a chance to
He's too chaotic and unpredictable in that form, he literally has the power of biblical cataclysm on his side, like I'm talking universe shattering power.
Thrull is an agent of the fallen Coritan Empire. Eggyhead is in-lore an agent of God who was chosen to wield a small little bit of the universe breaking power he wields.