Surprised by Chalk's unexpected behavior, he laughed and replied, "Oh ho-- it seems there's more to you than meets the eye Chalk... well now--" his speech was cut off as he coughed up black liquid which stuck itself to his mask, blocking off portions of the airways and making it harder to breathe.
Just as he was about to pull off his mask with his left hand -- it began to twitch and contort, the skin blackening -- becoming enveloped in the liquid which violently erupted from the lip of his glove and from the point in which he injected himself.
The same liquid began to spread across his face from his mask -- merging his skin and the mask together until his face and leaving nothing but an indistinguishable darkness with white ovals for eyes. Puffs of gray air emerged from the sides of his head as a horn grew out of the left side of his skull...
His body having locked up during the metamorphosis, fell to the ground as a fluid black tail pierced out from the tail of his spine.
On all fours, Seven finally regained control of his body -- breathing heavily through what was now his mouth and nose.
His eyes scanned the floor for a moment before looking at his left arm that was now a pulsing mass of dark liquid which responded as his mind clenched the nerves that were no longer there. Phantom effect? How interesting... he thought as he strained his mind to see if it were possible to control its shape -- successfully forming the liquidy hand into a large spiked claw. Brilliant! The mind controls the medium! Such a finding! The mind encompasses the entire body... not merely just the nerves! he thought, absorbed in his fascination.
Looking at his right hand -- he was surprised to find it having retained its human form. He scanned the rest of his body, learning that the right half of his body remained mostly untouched -- it seemed that the sample was only enough to propagate itself through the left side of his body. He found the horn on his head and the tail which swept itself to his side the most peculiar... not quite sure of the horn's functionality other than aesthetics.
Hearing Lark's voice... he wavily stood up. His feet planting itself -- Seven laughed, his laugh deep with bass that resonated around him.
"Oh this is brilliant! Even my voice has changed!" he cried in a monstrously deep voice -- a result of the black liquid in his vocal chords and the mask which was now his mouth.
"HaHAHahHAHa! More subjects you say?! Like her??" he replied, consumed by his madman's lust, and twisted his body violently towards the celestial -- his left arm crashing into her skull like a spear-thrown hammer, leaving a bloody mess -- parts of which found itself on Chalk's body.
"Oh... dear Chalk... how cruel art thou... ye who could not pull the trigger," he said as he saw Chalk holding the gun, "Don't worry -- she's a phoenix remember?! I only gave her the mercy she could ever receive!!! A quick and painless DEATH!"
Looking back at Lark and reeling his arm back with his mind which was now accostomed to its newfound arm, he responded to her offerings, "Ah! So where we... more subjects eh?! But what is this you speak of in JOINING... you? What if I want both the girl and YOU and EVERYTHING?" he paused, laughing for a moment, before apologizing and continuing on, "Oh...now now... don't misunderstand -- I would love to work with you...... side by side...... I could study you and modify you to your liking... and you could gather me subjects to study and draw your modifications from..." he paused again, trying to keep himself from laughing as he said, "...almost like lovers looking out for each other!!"
As he finished his sentence, he began to laugh maniacally, commenting on how entertaining yet stupid of an idea that was -- as if a sarcastic joke thrown like salt on a wound.