A zombie boule is a boule that is knocked out of bounds, hits something, rebounds back onto the terrain, and moves or deflects still-living balls (boules or jack). That is, it is a boule that has died and then come back to life to attack the living.
Article 18 of the FIPJP International Rules of Petanque creates zombie boules and tells us how to deal with them.
“Any boule is dead from the moment that it enters an out-of-bounds area. … If the boule then comes back onto the game terrain… it is immediately removed from the game and anything that it displaced after its trip through the out-of-bounds area is put back in its place.”
The problem with Article 18 is that it is impossible to put into practice.
In Real Life, the original places of balls are never marked, so it is impossible to put things back in their original places. And who knows what “original place” means for a ball that was in motion when it was stopped or deflected by a zombie?
As a consequence, Article 18 gives rise to an unending stream of “What do we do if…” questions on petanque forums.
A zombie boule is a boule that is physically alive after it is legally dead.
Therefore, the simplest solution to the problem of zombie boules is to consider boules to be legally alive as long as they are physically alive.
A boule that goes out-of-bounds and then comes back in-bounds should be considered legally alive until all balls in the game have come to rest (stopped moving). Then it should be declared dead and removed from the game.
With this solution, there will be no encounters between living and dead boules, and no problems about how to put things back in their proper places after such an encounter.
The way to implement this solution is to change Article 18.
“After all movement caused by a thrown boule has stopped, any ball (boule or jack) that left the game terrain, or left and then came back onto the game terrain, is dead, and is immediately removed from the game.”
Aside from putting an end to zombie-related “What do we do if…” questions, this change would have absolutely no effect on the way that the game is actually played.
Umpires currently ignore Article 18’s command to put things back in their places because that command is impossible to obey. So they invariably rule (a) that the dead boule should be picked up, and (b) that since none of the original positions of the other balls on the terrain were marked, everything else stays where it is. That is exactly the same as what they would do if the revised version of Article 18 were to be put into effect.