After you shot Faldi, you were teleported in the hallway that leads you to SpongeBob's office and you enter inside SpongeBob's office, and you see Rob a red sponge and he is just serious, and he sighs after what you did to Faldi after you shot him.

Rob: "I don't understand why you did this. You shot a person, to get in this room. Just let that, let that thinking. You shot a person, to get in this room. Like, why? Like if you haven't found lore or secrets like why would you shoot a person? He owns his shop, and there's no reason to shoot someone. Like he gives you free items free of charge. Like, why would you... Why would you do that like that's pissing me off. Why would you... Why would you do that to someone? Like if you wanna see lore, I'll show you lore."

Rob starts to scream, and you get teleported outside, and you got inside Spongehouse and Rob is going to come after you. Find all 12 Spongybooks and get to the cafeteria exit and make sure beat Rob.

Fun Fact: When you get to the boss fight. You throw poison potions at Rob, and he will be the boss fight that he will have 20 HP for this boss fight that you will have to throw poison potions to make his health go down.