Rules question

[zacem]

If a creature enters and does not cause any triggers to go off, does your opponent get priority? More specifically, once my Sporemound has resolved, can they kill it before I play a land?

[WizardSpartan]

No, your opponents would not get priority in that instance. When you cast a spell, each player gets priority. Once priority has cycled by each player, that spell's effects happen/it enters the battlefield, and you gain priority.

In Sporemound's case, you get 1 land trigger for free before your opponents regain priority.

For example, this is is also the reason why you get 1 activation from a resolved planeswalker before your opponent can remove it.

Hope I explained it well!

[Judaspriester]

While WizardSpartan is correct, I would offer another (better?) explanation why this doesnt work:
Lands don't go on the stack.

In order to explain this further, here is an counter-example:
First you play Angelic Chorus. The priority goes round, the spell resolves, Angelic Chorus enters the battlefield (without triggering anything). If you now follow up with another creature, you'll open a new stack and before it resolves, the priority goes round again (which means your opponents could do something against Angelic Chorus).

For your case with Sporemound and a land, the first effect that hits the stack is Sporemound's triggered ability. This means even if they destroy Sporemound now, you still get your first token.