If you missed it yesterday, here is the comic. Below are the answers.

Keith Hackett's verdict
1) You haven't covered yourself in glory here: you should have been aware of who was, and was not, on the pitch before the kick was taken. As it is, disallow the goal, caution the scorer for re-entering the field of play without your permission, and allow one of his colleagues to retake the penalty. The player can return to the pitch at your signal. Thanks to Bongai Jingur.
2) The rules governing a penalty shoot-out have changed to include this proviso: "The referee must not abandon the match if a team is reduced to fewer than seven players during the taking of kicks from the penalty mark." So there's no abandonment: the shoot-out continues. Thanks to Matt Bennett. This answer was corrected on 23 December – apologies for the original error.
3) What a mess. Try to calm everyone down, then take it step by step. Check the boy is unhurt and make sure he is escorted away. Then show the striker a red card for committing a violent act, and the home captain a yellow card for unsporting behaviour. Restart with a dropped ball on the goal area line, parallel to the goalline, at a point nearest to the incident. Include it all in your report.