The Stack

 If I have in play treacherous pit-dweller and a nephalia smuggler with enough untapped mana to use smuggler. And somehow pit-dweller goes to the graveyard and triggers undying.

My first question triggers many,
   The pit-dweller enters the battlefield, triggering its first ability to change control to target opponent and putting it on the stack?
   If pits ability is on the stack, I can target pit with smuggler and blink the pit-dweller's ability away?
   If pit returns this way, it's +1/+1 undying counter doesn't return with it?

You can do that it loses it's counter when exiled

If I have in play treacherous pit-dweller and a nephalia smuggler with enough untapped mana to use smuggler. And somehow pit-dweller goes to the graveyard and triggers undying.

My first question triggers many,
   The pit-dweller enters the battlefield, triggering its first ability to change control to target opponent and putting it on the stack?
   If pits ability is on the stack, I can target pit with smuggler and blink the pit-dweller's ability away?
   If pit returns this way, it's +1/+1 undying counter doesn't return with it?

1)  I'm not sure if that was a question or more of a statement, but yes.  Unless it had a counter on it, undying will bring it back.  When it reenters, the triggered 'Donate' ability will go on the stack.  Along with the soulbond trigger.  Since they are your abilities you may chose the order to put them on the stack. 

2)  If you chose to put the donate stack on the bottom of the soulbond trigger (which is the smart play here), then you can activate the smuggler's ability to flicker the pit-dweller.  Since it is coming back from exile and not from the grave, the donate trigger won't happen again.  The earlier trigger will lose track of the dweller after it leaves play.

3) yes.

I'm new to the magic world and was wondering, and don't think I'm stupid, but how many cards should be in your library during a duel

I am an older player I stopped buying around mirage so I have a question. Using a red burn deck i play aether flash and my opponent has 1 relentless rat in play, on his turn he plays a relentless rat, so my question is they are both triggered abilities so do the resolve in lifo or does the rat take the damage as he comes into play and they do not get the +1\+1?

I am an older player I stopped buying around mirage so I have a question. Using a red burn deck i play aether flash and my opponent has 1 relentless rat in play, on his turn he plays a relentless rat, so my question is they are both triggered abilities so do the resolve in lifo or does the rat take the damage as he comes into play and they do not get the +1\+1?

It would make a lot easier if you linked the cards. Use and out the card name in between.

One could also be courteous and just say Relentless Rats and Aether Flash, Kuberr.

Anyway, the flash wouldn't kill the second Rat since the +1/+1 is a static effect, so it enters as a 3/3.

The stack works as filo and if two abilities would trigger at the same time active player goes on stack first since he's playing a creature that means his stuff goes on stack first

But this wouldn't matter because after looking at the cards the rats effect is static and doesn't use stack

I'm new to the magic world and was wondering, and don't think I'm stupid, but how many cards should be in your library during a duel

In a constructed deck, your library mist be a minimum of 60 cards. It is usually recommended to stay as close to the minimum as you can, as you will be more likely to draw the cards you want.

In a limited format (a draft game or a sealed game) the minimum is reduced to 40, because you have to make your decks from unopened packs on the spot.

Yeah sorry about the link thing this is my first time posting on here but thanx maximo for the clairification.

And i understand how the stack works i was just confused on the static on the rats.

Ok cause u asked if it was LIFO and that's not how it works

My mistake filo LIFO same thing

How does tamiyo ultimate work with mana leak? It just seems like at some point my spell should resolve before getting another mana leak played since it goes back to his hand :/

Can you explain it a little better Spells don't go to the graveyard until they resolve

How does tamiyo ultimate work with mana leak? It just seems like at some point my spell should resolve before getting another mana leak played since it goes back to his hand :/

Are you asking what happens to the mana leak if its caster has tamiyo's emblem in play, or what happens to a countered spell if the countered spell's owner has the emblem?

If the owner of Tamiyo the Moon Sage casts a spell and it gets countered, that spell would go to the graveyard, but the emblem says "nope" and it goes back to his/her hand.

If you're asking what happens to the mana leak if it's controller has the emblem, I'm not 100% sure because I forget when instants/sorcery cards go to the grave.

I don't think this is correct but If they go to they graveyard immediately and just their effect is added to the stack, then you would in theory have the same mana leak to use again in the same stack.
But I think the card actually goes to the graveyard when its effect happens and the spell resolves, so you wouldn't get it back in hand until the leak resolves, at the bottom of the stack (aside from the original spell it's targeting). Jester, can you confirm or be /hatin'?

Either way, I'm pretty sure you can cast mana leak (or stifle or counterspell) on top of a large stack, get it back when it resolves at the latest (possibly immediately), respond to the spell resolving by adding it again because it's in your hand again, and repeat to cancel the whole stack no matter how large, as long as you have the mana.