2022-09-09 : As Benalish Sleeper’s ability resolves, first the player whose turn it is chooses a creature to sacrifice, then each other player in turn order does the same knowing the choices made before them. Then all those creatures are sacrificed simultaneously.

2022-09-09 : If you kicked it, you may sacrifice Benalish Sleeper itself as its ability resolves. If you control no other creatures, you’ll have to sacrifice Benalish Sleeper.