Along with learning proper Spanish, picking up some of the local slang words is unavoidable. These words get used so much in everyday speech—and because a huge part of my language education is comprised of striking up conversations with anyone who seems friendly and inclined to talk to me—that I have had to learn them, simply to understand what is being said.
Literally, no hay culebra means “No snake” or, “There is no snake”, and a dictionary can’t help you here, it is only likely to confuse you.
It is used, for example, at the market…when some vendor tries to overcharge me for something. It never fails to get them to lower the price to something more usual (not necessarily a bargain, but at least the price for locals, and not the extortionist rates levied on foreigners).
An expression known mainly to Caraqueños (from Caracas), it almost always gets a delighted laugh when I use it, because it is so slangy. A lot of Venezolanos, from other parts of the country, are unfamiliar with it.