When Sandsteppe Outcast enters the battlefield, choose one — • Put a +1/+1 counter on Sandsteppe Outcast. • Create a 1/1 white Spirit creature token with flying.
2014-11-24
If a mode requires a target and there are no legal targets available, you must choose the mode that adds a +1/+1 counter.
2014-11-24
You choose which mode you're using as you put the ability on the stack, after the creature has entered the battlefield. Once you've chosen a mode, you can't change that mode even if the creature leaves the battlefield in response to that ability.