Who's dying? You choose

[Subiskier]

{oracle en-vec} + {sleep}
Tap oracle, player chooses attackers. Play sleep to tap everyone. When they don't attack they die.

[Double-O-Scotch]

What if your opponent just chooses no creatures?

[Subiskier]

Then don't play sleep. Guess it works best before they know your combo.

[FlickerYourOwnIdentity]

Wait, if they don't choose creatures, then don't they die as per oracles effect. 
And if not what if you subbed oracle out for {Siren's Call}?

May have red wrong, I'm tired.

[Subiskier]

{sirens call} good find. That's a perfect card for that thanks!

[Mactitioner]

 {Icy Manipulator} +  {Arcum's Whistle} similar effect and works in all EDH decks because of artifacts