Originally Posted by
Megadeus
If you are attempting to destroy a chalice with the ratchet bomb (which I am assuming is your goal by the way you posed your question), then you want to blow up ratchet bomb with 0 (none) counters on it. When chalice is on the battlefield its Converted Mana Cost is 0. When it is being cast (where X=1) then the converted mana cost on the stack will be 2, but right when it hits the battlefield anything that would destroy or get rid of something that is CMC 0 will take care of chalice.
As for your second Question: Storm and dredge can be hurt by Extirpate. Needle against these decks is marginal as it cannot be used to stop mana abilities, which lion's eye diamond is. So naming LED with needle will do nothing. Against Dredge the best Needle target I can think of would probably be Cephallid Colosseum. I'm not sure how effective that would be against them however. Against Dredge Extirpate is kind of tricky and depends on the situation. You could always Extirpate their Narcomeoba after it hits the GY with the trigger on the stack, or hit their Ichorids possibly since you may have a tough time dealing with those yourself. I'd say hitting bridge is alright, but you can get rid of Bridge many ways such as animating your mishras factory and killing it via, smallpox, wastelanding it, or even innocent blood. Dread Return is an option if they end up on that plan, but I think in that case you would rather them flash back the Dread Return and simply extirpate their target.