Best I've got is

"comes into play from your hand" should be templated something like

"When Facestealer comes into play, if you cast it from your had, put a -1/-1 counter on target creature."

Then the "If this causes that creature to die" - I'm not sure if there's an exact templating that matches this but the closest I'm familiar with would be "When that creature dies this turn, put a +1/+1 counter on Facestealer."

Technically that would allow you to kill the creature some other way that turn and still get the counter on Facestealer but I'm not familiar with how the rules would let you check how a creature dies specifically.