Mettaton vs Bete Noire (Battle)

Context
After being informed of Alphy's death, Mettaton decides to avenge her as well as stall her until Chara and the Dreemurrs arrive. Isabelle is instructed to fetch Mettaton's case, which allows him to transform into Mettaton NEO while he fights Bete in the arena.

Battle
The battle begins after Bete breaks through the shield protecting the arena, successfully killing three guards in the process. Outside the arena, Bete sees a trembling Seth and attempts to kill him. Before she can do so, Mettaton uses a spotlight to fire at Bete, preventing her from moving. Upon further investigation, it is noticeable Bete takes a small amount of damage when attempting to move. The spotlight possibly has the same mechanic as the 'blue attack', in which the target must stop moving to survive. While Bete is restrained, Mettaton grabs Seth and tells him to find somewhere safe. Bete breaks the spotlight and throws Mettaton into the arena, and jumps into the arena herself.

Meanwhile, Isabelle manages to throw the NEO suitcase at Mettaton. Mettaton successfully catches the case and transforms into the iconic Mettaton NEO, while dodging an attack by Betty. Bete attempts to attack Mettaton but, Mettaton blocks it and fires his own attack at her. Bete's skin is seen falling off, leading Bete to say how it hurt "a little".

Then, the fighting sequence begins. Bete jumps into the air and a dark, pink attack which Mettaton outruns. Before attacking, Bete states she’ll play with him. She fires another attack which Mettaton, again, runs from before turning and firing at it- causing an explosion. Before the explosion can clear, Mettaton fires another beam at Bete, but she manages to dodge. Bete attempts to grab at Mettaton but, is propelled away once Mettaton activates his leg boosters. A glimpse shows Asriel sitting on support beams observing the ongoing battle, and possibly waiting for Chara's arrival. Upon noticing the large chunks of debris from the arena, Bete is quick to throw them at Mettaton, taking him by surprise.

After making another one of her otherwise iconic creepy expressions, Bete hurls more large chunks of rock at Mettaton. Mettaton attempts to counter the debris with an attack, but out of the smoke comes one of Bete's spears, piercing his shoulder. She then jumps, using Mettaton's moment of surprise to gain the upper hand, and taunts him before slamming him into the ground. Bete proceeds to prepare the final blow when she is suddenly attacked by Muffet! Muffet traps Bete in a series of spider webs, in which Grillby then attacks. Both attacks combined causes an explosion, prompting Mettaton to interrogate Muffet on why she is here. Muffet responds saying she couldn’t watch Mettaton die. Mettaton’s circuitry starts to malfunction after enduring so much damage. Bete attacks Grillby, throwing him into the wall before hitting Muffet. Knowing he must protect his friends, Mettaton plugs himself into a large spotlight and, with the last of his power, fires desperately at Bete. The spotlight damages Bete, ripping off clothes and skin as she starts to walk closer to the source. Summoning the same attack used to break the shield protecting the arena, she fires at the spotlight, destroying it. Bete is seen appearing in a form that resembles Agate, during which her eyes flash green briefly.

After destroying the spotlight, Bete turns her attention to a crying Isabelle. However, a damaged Mettaton grabs at her leg, stating that if she wants to hurt anyone, she'll have to kill him first. Bete asks Mettaton why he even would even bother when he knows he can’t win. Mettaton responds he just needed to make time. In an instant, Chara runs into the arena, headed right for Bete. Bete tries to escape but cannot move thanks to Mettaton's grip on her leg. Chara then sends Bete flying into a wall, while Toriel tends to Grillby and Asgore tells Muffet to find a safe place. Bete begins to rise before Chara demands her to stay down. He then fires a beam from his sword, which is blocked by Asriel. Bete asks if Chara thinks she’s the only thing he should worry about. The scene fades.