MTG: Silence question?

During my opponents turn upkeep I cast Silence. While I'm sure they could play an instant "In response to" my silence(am I right?), could they cast a sorcery or creature with flash? And how does the whole "You play card X, so I play card Y in response" thing work?|||Yes, they can play Instants in response to Silence, because it has no effect until it resolves.








Normally, they would only be able to play an Instant or something with Flash, or activate an ability, as everything else operates at Sorcery speed.








The whole 'playing in response" system revolves around the Stack, a very important concept to understand in Magic. The Stack is where all spells and (non-static) abilities go when they are played/triggered/activated. The Stack functions in a FILO (First-In-Last-Out) mechanic, so each item on it has to wait for everything else that has been put on more resently to resolve before it can be resolved. Dealing with a series of spells demonstrates it visually quite well.





Lets say I have 3 Llanowar Elves on the Battlefield. I cast Overrun, so it goes on the stack. My opponent sees this would be a major problem for him and casts Volcanic Fallout in response, so it goes on the stack on top of the Overrun. I respond by casting Giant Growth on one of my Llanowar Elves. Both of us decide not to cast any more spells, so Giant Growth resolves and gives the target Elf +3/+3. Then we both again decide not to cast any spells and the Volcanic Fallout deals 2 damage to each player and each creature, killing the 2 elves that were not targetted by Giant Growth. Then my opponent decides to cast Terminate on the remaining Llanowar Elf, so it goes on the stack on top of the Overrun. I choose not to respond, so Terminate resolves and kills the Elf. Then we both decide not to cast anything and the Overrun resolves. Finally, the stack is cleared.|||Anything wish flash can be cast at instant speed. yes even a creature. however its abilities must be activated abilities and not tap or conditional to take effect.|||flash counts as instant and folow the rule first in last out.