There was one point in time where NXT was at it's lowest of bear markets and I noticed I could short it to zero using only something like 6 BTC for the hell of it (I forget if NXT even had leverage enabled - probably not but I think it did).  Even though it would be an incredibly stupid idea, I almost did it anyway.  That's probably the closest you'll get to an altcoin reaching 0 until bitcoin itself dies from people noticing a combination of being designed to centralize and non-fungible makes it the ultimate new world order slavery system.