Excuse me, may I use your phone? I have an important call to make.

There is a young guy standing in front of you. He looks harmless so you give him the phone. He puts the phone to his ear, even though he hasn't even dialed the number. Before you could ask a logical question, the guy bitterly grinned to himself and handed the phone back

I'm sorry to bother you. I forgot again that he was already dead.