What do these two mean?
 

ギッタギタにプッ殺してやる

ギッタギタ　And プッ　 what do they mean? slang or something?

Thanks in advance

Man, what have you been reading? Certainly not the best of our literature...:D

These are not really slang but very colloquial phrases.　

ギッタギタ　＝　ギタギタ　= extremely greasy　

ブッ殺す　＝　that's how someone in a rage says 殺す when he is about to kill another. ブッ adds a furiouness to the verb that follows it.

Thus, ギッタギタにプッ殺してやる literally means 'I'll kill (most likely by stabbing, not shooting) you in such a way that the floor (or ground) will get so greasy'.

I can't believe I did this post while eating a pork chop for lunch....

Wow thanks. I didnt know there was adding furiousness kind of words