Sonic was visiting Tails' house while he was working with some liquids. "Hey Tails, what are you working on?" asked Sonic. "It's a combination of liquids, but I don't know what it does," said Tails. "Does it work on animals like us?" asked Sonic. "I'm not sure. I haven't tested this liquid yet, so is it okay if I could use you as a test subject?" asked Tails. "As long as nothing bad happens to me, then yes," said Sonic.
Tails took out a beaker and let a drop of the liquid fall onto Sonic's left shoulder. Sonic felt a ton of pains all over his body as the tan fur on his belly reshaped itself into a heart. The cuff on Sonic's right glove turned orange while the cuff on the other glove turned purple. Sonic's head slowly moved to his right shoulder and he looked to the left. An exact copy of Sonic's head slowly grew from Sonic's left shoulder while two gold coins formed on each of Sonic's shoes.
"This isn't good, Tails. You should've brought in Amy instead of me," said Sonic as his second head stopped growing. "What the heck? Where am I?" asked Sonic's second head, which caused Sonic and Tails to freak out. A white necklace appeared on Sonic's first head while a black necklace appeared on Sonic's second head. Sonic then felt like there were two bodies inside of him since he now had two heads.
"How can this be? I didn't mean to do this!" said Tails. "Is there a way to undo this?" asked Sonic's first head. "Please don't undo this, Tails! I just appeared on this body!" said Sonic's second head. "Okay. I'll call the left head 'Sora' and the other head 'Nicky' so I don't get confused," said Tails. "Okay! See you later, Tails!" said Sora and Nicky as they walked outside and went up to Amy.
"Sonic? What on earth happened to you?" asked Amy. "It's a long story, but Tails gave me an extra head when we used me as a test subject," said Sora. "What did he test on you?" asked Amy. "I've only been on this body for a few minutes, so I don't even remember," said Nicky. "Okay, this is freaking me out. I'll see you both later," said Amy as she walked away in fear. "We did it, Nicky! Thanks to you, Amy won't bother me anymore," said Sora as Nicky smiled. The two-headed hedgehog went to Sonic's home and eventually found their own interests for each other.