Enter the battlefield triggers with no legal targets

[lordofthepit]

If my opponent plays Show and Tell with no creatures on board, and he drops an Omniscience and I drop a Stingscourger, does Stingscourger's trigger get put on the stack at all (since there are no legal targets)? I am specifically wondering whether I have an opportunity to play instant-speed spells/abilities with the trigger on the stack before my opponent is able to play sorcery-speed spells.

(On different but tangentially related note, if my opponent plays Show and Tell and he next-levels me by dropping a land (with no non-land permanents in play) and I drop an Oblivion Ring, I must remove one of my own nonland permanents if I have one, correct? This seems pretty clear, but I just wanted to confirm.)

[Malchar]

Once an ability has triggered, its controller puts it on the stack as an object that’s not a card the
next time a player would receive priority. See rule 116, “Timing and Priority.” The ability becomes
the topmost object on the stack. It has the text of the ability that created it, and no other
characteristics. It remains on the stack until it’s countered, it resolves, a rule causes it to be removed
from the stack, or an effect moves it elsewhere.


The remainder of the process for putting a triggered ability on the stack is identical to the
process for casting a spell listed in rules 601.2c–d. If a choice is required when the triggered
ability goes on the stack but no legal choices can be made for it, or if a rule or a continuous
effect otherwise makes the ability illegal, the ability is simply removed from the stack.

The trigger will go on the stack, but it will be removed by the game rules before anyone gets priority. The active player will receive priority at this time, and since the stack is empty, he or she will be able to cast sorceries. For the oblivion ring question, you always have to choose targets if able. If a legal target exists, you must choose it.

[lordofthepit]

Thank you!