I panicked. We did.
While I simply wanted to scream, for my borrowed mind it was instinctive defense, sending a lash of roiling, boiling emotional memories from the dark corners of my mind boiling towards Luna in a black-red cloud.
Her horn glowed again, and a bubble of something snapped into place around her, dispersing the cloud.
Around her my constructed dream dissolved into nothing, leaving us floating in the depths of my alien mind. With a visitor inside, it looked less abstract than I recalled, more constructed, like a vast, suspended library inside a cavern that stretched out forever. Here and there were missing bits, or places I could not comprehend with my human mind so far out of sync with the monstrous shell it inhabited.
She still held her shield, set for any further assaults.
We floated there a while, until she slowly lowered her own defenses and simply looked around, taking it in and smiling reassuringly at me. "Be not alarmed Changeling. I merely wished to see if there was more to thee than a simple grass plain." She floated down, a gesture of my mind summoning simple resin-like pillars to stand on. "I am, to say the least, pleasantly surprised." I swirled like black mist to walk by her side through my mind's archive, pillars rising up to meet our feet.
Luna examined the pillars, and the archives around us, looking closely at the vast volume of tightly packed 'books' of knowledge and memory. I allowed her to look, and followed as the lunar Princess walked between the shelves "A full mind.. May I peruse one? T'would be interesting to see things as thine species does, if only for a moment."
I considered the idea, and smiled just a little "very well your majesty, you may. Not all of these, I would warn you, are my own."
She turned, a slim black volume already in her field, and quirked an eye "oh? If not thine, then whose?"
I let a little predator shine through there, the knowledge unfolding in my mind within the mind "some are copies of those of my victim's. I study their minds to better emulate them, to further the masquerade as it were." In truth, that worried me, it made me realise, even further, that I was the bad guy here; an emotion, memory, identity stealing monster. If there's one thing you learned from watching MLP, it's that Bad guys don't last.
Luna simply hummed, turning back to the tome in her aura and quirking an eyebrow "be that as it may, changeling, whose memories are these?" She turned it upside down and then sideways, narrowing her eyes at the cover "I do not recognise this language.. if it can be called such." With annoyed huff she floated the book my way, showing the simple rectangle of alien, odd text adorning the hardened resin cover.
I didn't know the language either, for a moment it was as foreign to me as the blibble-blobble of fish to anyone but Fluttershy. It seemed to be comprised of little but jagged, geometric lines with dots accenting it. Then comprehension bloomed like a flower, and a rustle went through the space of my mind, ruffling the pages of my archives as a short, powerful wind. My eyes flashed green for a second over the blue and I smiled.
I must have stood there for a while, because soon Luna risked poking my side with a careful wing "Changeling, art thou okay?"
I blinked with the eyelids I didn't have and nodded, turning with the book floating to rest between us "Very much so Princess, I merely lost myself in thought for a while.." The book floated up and began to open, green light erupting onto our faces "..This is one of my favourites, a simple little memory, detailing a very.. interesting day in Ponyville. From one of my long term agents, named..."