The speech of the 1st person is a jargon, which is similar to a thief one. The verb "бичеваться" means behave oneself undeserving, like a "бич" - a homeless and/or despised person. "Веди нормально" - it means or just "behave yourself", then it must be "веди себя нормально", or "drive a car properly". "Херово" = bad. This word is obscene, don't use it. The common meaning of the word "паук" is a spider, you're right. In the thief conceptions a tattoo which is pictured a spider can mean different things, that's depend on a specific image of it, its place on the body of a felon, accompanying things on the tattoo, etc. For example, it can mean a leader of a band, or just a thief (with signes of his specialisation), or a drug addict. In this way, as far as I can judge, the 1st person congratulates the 2nd one on getting of a spider tattoo. "Друган" = a friend.

i just dont get it... spider? i think thats wrong or?

Where from did you get these... khm... expressions at all?