The trio of friends glanced (well, two of them did) around Erin's empty room, careful not to tread on the glowing goo on the carpet. Katie asked questions about the surrounding area, trying to piece everything up in her mind.

"Whatever you do, don't touch to goo. It's highly alkaline and I don't want to have to counter it with acid." She demanded. April knelt near the goop and of out a gasp as she realized what it was. "What? What is it?" Katie asked, lifting her head. April glanced at Zoe.

"Zoe, I need to talk to Katie in private, do you mind?" April asked. The girl nodded and exited the room. April sighed and began leaning towards Katie and whispered in to her ear. "Remember what Donnie said? About him and the others being mutants? That goo, it was what turned them into what they are." Katie let out a horrified gasp, the pieces clicking inside her head. Her hand covered her mouth in shock. It made sense. Maybe Erin got really curious and touched the goo, even when Katie specifically told her not to. That meant...

"That means she's been mutated. And she's somewhere out there!" Katie exclaimed. "We have to find her. Do you think your turtle friends can help us?" She wondered, grabbing onto April's wrist. The red-headed female hummed before nodding.

"Yeah. I'm pretty sure they will." April helped Katie up and the two headed out of the room. She turned to Zoe. "It's gonna get late and the streets aren't really safe. I think we should head home and wish for the best." Zoe raised her eyebrow curiously but nodded.

"Yeah. I'll see you whenever, then. I'm gonna stay here for a little bit." Zoe answered. April and Katie quickly exited the house and made their way. Zoe watched them with a frown before pulling out a test tube and rubber stopper she pinched from Katie's school bag while no one was looking. She knelt down beside the small bit of goop on the carpet and put it into the test tube without touching it, putting the rubber stopper in the opening so none of it could escape. She put the test tube in her pocket after making sure the stopper was safely and securely on. Quietly, she exited the house and made her way home, touching the test tube unconsciously.

April pried open the manhole down an alleyway and leaped down before catching Katie as she dropped down. The two girls headed down the sewers, Katie pinching her nose in slight disgust at the rancid smell. Soon, they came to the area the turtles stayed and April called for them. Katie tensed up when a hand grabbed her shoulder but relaxed when she realised that it was one of the turtles. She breathed a sigh of relief and April started to speak.

"Hey, guys. We have a missing friend. The auburn-haired girl you once saved. She found a canister of mutagen and we suspect she's been turned into a mutant. We need your help to find her." She informed the four reptiles. Katie nodded, taking a step forward before her foot hit something. She stumbled and was about to fall when Donnie caught her. She sighed in relief, resting a hand on his shoulder. She smiled in his direction.

"Thank you." Katie said. Donnie chuckled slightly.

"So, do you know if your friend had come into contact with any animals? She might have transformed into that. It would definitely narrow down our search." He asked. April hummed, tapping her chin in thought.

"Not that I know o-"

"Hold on, April! She went to the Zoo with Zoe, remember? She had touched a wolf!" Katie stated, making April's eyes widen in realisation. "She could be a wolf! Didn't you see the cut on her finger? When she touched the wolf, the DNA could have spread inside her system and stayed there. When she touched this, what did you call it, mutagen? When she touched the mutagen, her DNA could have fully merged with the wolf's DNA which was probably still lingering in her system!" The turtles then looked amongst each other, having a silent conversation before looking at the two females. Katie had gotten it right and the turtles knew who they were looking for.

"We might possibly know who you're searching for." Leo muttered. "I ran into a lone mutant down here last night. Come on. Was... 'her' name Erin?" He received two frantic nods. The group made their way into the turtles' area and immediately, the mutant wolf Leo had stumbled across looked up from his seat on the ground. He let out a gasp in shock.

"Katie? April?" The deep voice questioned. Katie tilted her head in confusion.

"Since when did you have Markiplier down here?" She questioned curiously. 'Erin' looked at her with a frantic look. He quickly got up and sprinted over to stare at April. April shook her head, staring at 'his' blue eyes in shock and surprise.

"Erin?! B-but... you're... you're a GUY?!" April exclaimed loudly. "HOW?! YOU'RE A GIRL! HOW DID THIS HAPPEN? I am so confused!" Katie's eyes widened and she stood there, unable to respond.

"M-maybe... I have a bit of a theory. Maybe 'she' had the DNA of a male animal inside of her and the mutagen picked up on that?" Katie suggested. "Erin? How are you feeling?" The Wolf grinned.

"Never better! I'm actually really content like this!"

"What about your parents?"

'Erin' paused before frowning. He sighed, scratching the back of his neck.

"I don't know, okay? I'm really happy like this, don't force me to change back." He pleaded.

"Why would we force you to change? Erin, we won't force you to give up whatever makes you happy. You're our friend. And we love you." Katie stated, making 'Erin' smile. "I'm guessing when spelling your name, we should change it to 'E-R-E-N', huh? Your favourite SNK character. Does that sound good to you?"

"Yeah! That'll be awesome!" Eren grinned again. "I'll remain here with the guys."

While walking home in the dark, Zoe just couldn't contain her curiosity and she pulled Katie's test tube from her pocket. She stared at the glowing green stuff and the urge to touch it grew stronger and stronger. Sighing, Zoe opened the test tube and held out her opposite hand before tilting the tube and pouring it onto the palm of her right hand.