Why did my contact lens turn dark grey/purple?

I didn't use my contacts for a few days, nothing unusual. I opened them up today and the right one was still clear, but the left has turned dark gray, kind of a dark purple color, the whole thing so that there's a very visible dark circle in the case. As if they were dark grey colored contacts or something. I've never seen anything like this before?

It means you've contaminated teh solution with something. You'll have to throw the lens out. To be on the safe side I'd throw the case as well and check that nothing is wrong with your solution although the fact the right one is o.k. Implies the solution is. Try the right one in your eye before using a new left lens to check nothing is wrong with that.