Melvin the Mentioned Previously's Mutantenous Mix-up

It was only as I was singing the last verse that I realised the horrific truth: I was not underwater!
How could I have been so foolish? I asked myself gruffly like a billy goat. There was no water in the cart apart from Krulnor's remaining tears, and there was in no way enough of these for me to possibly consider myself underwater.
However, stopping the incantation at this late moment could have disastrous consequences, so I finished the final words and winced in anticipation of whatever unexpected consequence was about to happen.

There was a distant rumbling, followed by a scratching noise, as if a small Scottish terrier with a white coat and a black patch over one eye, and with grey hair, was asking to be let out in order to 'do its business' in the privacy of the middle of the lawn.

BING!

To my great amazement, I looked down at the brand new hand that had appeared where my previous hand had been.
"Huzzah!" I yelled in a manner reminiscent of English Naval Officers celebrating a victory over previously undefeatable zombie-like pirates when the curse of immortality keeping their enemies from harm had been broken. I tried to clap my hands together in celebration, but to my confusion only my right hand responded, with the result that I slapped myself in the arm. My new left hand stayed where it was, unresponsive to my attempts at making it move.
"What's going on?" I muttered out loud, mostly to myself, and certainly not expecting a response to come from somewhere near my left shoulder.
"I was just going to ask you the same question" came a response from somewhere near my left shoulder.

Not for the first time, I screamed and leapt into the air, flailing wildly with my one working arm, and once again accidentally striking the tracker in the face. Landing, I twisted to the left, and came face to face with a face staring back at me.
I screamed again, and would have once again leapt into the air, but before I could my up-til-now unco-operative left hand slapped me in the face, shocking me into stillness.
"Calm down!" the face ordered with such authority that I immediately obeyed.
"Who are you?" I asked as calmly as I could muster (any farmer would have been proud at how well I mustered).
"I'm Melvin the Incredible" the face replied.
"And this is my left hand" he continued, as my new left hand waved about to demonstrate Melvin's control over it.
"So, what are you and your hand doing attached to my body?" I asked.
"I have no idea," Melvin admitted, "I haven't seen a result like this since Edgar the Fascinating tried speaking the incantation for 'Long Distance Relationship' without remembering to be underwater. He had recently lost his left hand to black market goblin snot traders, and the fool ended up with Sneebly the Inconsequential's hand and head attached to his body for months! It was hilarious, looking back on it. Although, looking to the present, not so much. Of course, how this result happened I have no idea. Edgar the Fascinating was a complete moron, and besides, the potion now has a warning label to prevent such a reoccurrance."

Subtly, I glanced down at the potion ingredients, and took in the "CAUTION: Reciting Incantation Whilst Not Underwater and with Missing Hand may result in Fusion with Target of Potion."

"Yeah," I scoffed loudly, trying to act outraged, "Who would do such an idiotic thing as that?"

Prior Event **** Subsequent Event