Before the audience had the time to react, Frisk and everyone else filed backstage where they found Papyrus, Undyne, and Mettaton all at a standstill.
Papyrus and Undyne were holding up Mettaton by his arms while the latter was struggling to escape.
Napstablook flew behind Frisk and put a ghostly hand on his shoulder.
"You did great," Napstablook whispered. "I'm proud of you."
"Me, too," Alphys said rubbing her hand on his other shoulder. "Don't forget the plan."
"I won't," Frisk whispered before walking forward to approach Mettaton. "Hey, Mettaton. How did you like our performance?"
Papyrus and Undyne let Mettaton fall on the floor while Frisk turned on the recording app on his phone.
Mettaton quickly got to his feet, brushed himself off, and strutted over to Frisk.
"You ungrateful, horrible, tacky, nightmare of a human child!" Mettaton yelled as he got in Frisk's face. "You have been nothing but a pain since I brought you here! I offered you everything you could ask for! Money, fame, stardom! And what do you do? You disrespect me every chance you get!"
SMACK!
That slap was enough to send Frisk flying back into the wall before anyone could react causing his HP to drop by three points back down to 16 HP.
"Frisk!" Napstablook yelled flying over to the wounded human child. "Hapsta, stop this!"
"Stay out of my way, Blooky!" Mettaton snapped back.
"Oh, you son of a…" Undyne yelled before getting interrupted by a long-awaited voice.
"Hold it!" Sans yelled suddenly appearing besides them.
"Sans?!" Papyrus yelled in surprise.
"Sans?!" Frisk yelled as Napstablook helped him get to his feet.
"Mettaton!" Sans began pulling papers out of his coat barely trying to conceal his anger. "You see these? These are adoption papers. That means I'm one of Frisk's legal guardians! And as his legal guardian, I've come to take him home! Now, you're going to let me take him home before I take care of you myself! You understand?!"
Mettaton humphed and said, "Fine with me. The little urchin is more trouble than he's worth. You can have him!"
"Good," Sans said as his anger relaxed into a smirk. "Alphys, did you get all that?"
"Yes," Alphys called out peaking around the curtain to see the monitors broadcasting everything that had just happened.
"What?" Mettaton asked the moment before he realized he could hear his voice echoing. "What are you talking ab-…? No…"
Mettaton ran past everyone backstage to the stage to see a stunned and grumbling audience.
"I can explain…" Mettaton said before the audience began booing him.
Everyone backstage smirked in satisfaction as the boo's grew louder.
Sans walked over to Frisk and asked, "Do you want me to finish him off for you, kid?"
"No," Frisk said firmly. "I decided I want to be a pacifist. I'm gonna stick to it."
Sans smiled and said, "You are a better person than I am, Frisk. Let's go home."
"Can everyone else come?" Frisk asked. "We could celebrate."
"Sure," Sans said before turning to everyone else. "Okay, everyone, follow me. We're going to Grillby's. I know a short cut."
Everyone smiled and followed Sans out.
The only one who lingered was Napstablook who looked in his cousin's direction for a while.
Thankfully, Frisk noticed.
"Napstablook, are you coming?" Frisk called as everyone was walking away.
"Yes," Napstablook replied. "Thank you."
Napstablook sped up to the happy group, and they all walked away.