This is a place where people fight zombies. As Bart said, Commender will give a million dollars to the 2 winners in the end of this whole thing. Fire Mario & Lego Mario got lucky enough to be there. Everyone gets 1 plant or item, and has to be in a group of 2. Fire Mario and Lego Mario picked Wall Nut & Fire to help them. It may seem like they wanna help and save the world, but that is not the case. Daryl Dixon claimed the workers are corrupt. They want to keep a few zombies alive for money. They had made Lego Mario and Fire Mario skip a day.
Fire Mario and Lego Mario didn't believe in the corrupt Daryl Dixon claimed until a new rule came out just for that day. People would get payed the more they insulted Fire Mario and Lego Mario. This place also didn't allow Daryl Dixon because they claimed he was too good. This explains why there are so many zombies still, and how this place is still running.