I really just took it from the sentence; the evil serpent from genesis. Sorry to bring religion into this, but I just can't look at this Pokemon and not think of the garden of Eden (which is in the book of Genesis). The snake (serpent) in the story tempts Eve with an apple from the forbidden tree for those who don't know the story. It sounds pretty "evil" to me, and the design of this Pokemon is pretty sinister looking in the first place, not to mention the golden apple on its tail. The artist just screams "the evil snake from the book of genesis" and I wouldn't be surprised if he/she was inspired by it. I just based my submission fully on this Pokemon's design.
Serpent + Turpitude. (A serpent is a synonym for snake and turpitude is the legal designation for actions which run contrary to the good morals of society; in a way which is wicked, base and/or vile)
I really just liked it better than my othe creations. "Tantaliez" just seemed to focus too much on the apple temptaton and on no other aspect of its character. "Tantalivy" didn't seem to improve that name much at all either since it didn't roll off the tongue as well, and it seemed to emphasize its grass-typing in a completely unneeded way. "Hissidious" just evoked the word "hideous" rather than Hiss+insidious, and tat completely threw off the meaning.
And besides that, "Sertempt" and "Serpentice" were already taken :P
I really didn't wanna do a hiss related name, but then I went to the store today and walked by the cacti for sale there and one of the bastards stuck me with their thistles and I made a "ssssss" sound in pain, so I felt this was a very fitting name. Especially considering the spines around CaP's body and the malevolent connotation the word "hiss" brings to mind.
Also I have no idea if I did the IPA thing right? That whole thing confused the hell out of me.