They are a group of zombie killers, all named Gerald. There are 6 of them. They are kind of dumb sometimes. They knew something was up with Ronald McDonald, so they had to sneak a way to get there secrets. But of course, one of the Gerald's drives his car into the other 2 Gerald's car. Even dumber, he drove over them as well. One of the Gerald's decided to cannon ball the other 2, which resulted in all 3 being knocked out inside Ronald McDonald's place. Another Gerald also was droven there, but he hates fast food restaurants, which resulted in Ronald McDonald threatening to visit him soon. At the end, some of the Gerald's told Lego Mario and Fire Mario they were faking being knocked out, and hired them to Zombicon.
4 Geralds eventually get Fire Mario & Lego Mario to practice weird things, and meet the leader of Zombicon. They have to climb and jump up obstacles, which results in madness. The Gerald participate too and cheat, They just fly up. Fire Mario tries to use the cars to get up. It succeeded. Then they all have to get up the second. To get up to the third, they wall kicked their way up. They climbed to get up to the top. They are kind of douches, and didn't bother to wait up when Fire Mario drove his car to follow them. Gerald 4 due to his color, he is able to sneak in as a zombie, since his color is the same as the others. He broke into a lair of the zombies, and he stole a couple rocks. The excuse was he needed to study them to learn how to be a zombie.
The zombies had a plan to take them out. It succeeded well since they felt for the Germ Rocks. They were able to fight off a couple, but things started to take a turn. Hike Zombie came up and lied saying he can help. However, he just threw Gerald 3 and Gerald Leader on top of some high place. Diggy came into fight, but only to be knocked out... or was he. He pretended to be knocked out until Gerald 3 was distracted. Then he used his weapon to stab and cut Gerald 3 in the stomach. Gerald 3 finally died. Gerald Leader died after Cone Head pushed him off a cliff. The rest of the Geralds fought with Cone Head but lost badly. Gerald 4 drove a car in front of him, but Cone Head threw the car so far away he died in a crash. Gerald 2 was kicked after an army member of Zombie Force stopped on his head and it gushed. This left the final Geralds being Gerald 1 and Gerald 5.