Make the Call - Week 1/6-1/12

SUB DENIES OBVIOUS GOALSCORING OPPORTUNITY INSIDE HIS OWN PENALTY AREA.

Question:

What should the referee do when a player comes off the bench and denies an obvious goal scoring opportunity inside his team's penalty area?

What's the call?
Any cards?
What's the restart?

Answer:

Send him off for denying the obvious goalscoring opportunity.  
Restart with an indirect free kick for the opposing team from the position of the ball when play was stopped (see Law 13 — Position of Free Kick). 
Indirect free kick is for the offense of unsporting behavior (sub enters without permission). The caution could be shown first, before the red card for denying the opportunity but not recommended.