1) someone spewing nastyness from their mere presence
2) someone or something so nasty that it requires it's own definition
3) aka a nastadontist: being someone who specializes in being a nastadon and/or performing nastadonic acts
"That nastadon just put his tongue in my mouth, I think I just threw-up a little"
Nastadontist examples: "Two girls, one cup...need I say more."
"You nastadon, did you just shart yourself?"
Nastadon... Derived from the word Nastidon which was a pukemon(Pokemon satire). He was one of the 1337est of the 1337. Nastadon is just a side of his 1337ness and over threw the nastidon and is now the master of the 1337s. He pwns everything no one comes close to him.
Tempestwolf: Man u hear about that nastadon kid?
Gooses: Hell yeah that kid is fucking 1337 as shit man
Tempestwolf: Hell yeah he fucking OWNS!!!
Gooses: So fucking nasty