Welcome to chapter 3, I should tell you something I'm planning on bringing a character from another crossover here. I'm not going to tell you what it is you'll just find out for yourself anyway lets get on with this.

"You owe me a life debt, for what." Gumball wasn't sure if he heard this right.

"For throwing that object at Megatron so he would focus on you instead of me so I could stop him from trying to kill me." Optimus said.

"It was nothing." Gumball said."

"Now allow me to summon the rest of my team." Optimus raised his hand in the sky and shot a homing missile in the sky.

It was a little while before Gumball and Penny's family finally made it to where they are.

"GUMBALL." Nicole said in an extremely worried tone.

"PENNY." Mr. Fitzgerald said in an extremely worried tone.

Before they could hug them they saw Optimus Prime and freaked out.

"WHAT IS THAT THING?" Richard screamed.

"Guys it's OK he's a good guy." Penny said trying to calm them down.

"Penny get away from that thing." Mr. Fitzgerald demanded.

"Gumball you too." Nicole demanded.

"Guys Penny is telling the truth."

"I do assure you they are telling the truth." Optimus said.

Nicole still didn't believe it and said "Give us one reason why we should believe you."

"Because if it wasn't true then they would already be dead." Optimus said trying to make them realize that it was the truth.

"He does have a point there." Richard said.

After that 4 vehicles appeared a yellow camaro, an SUV, a Hummer, and a sedan. They thought they were regular vehicles and were wondering why they were there, but when they didn't think anything else could go weird they transformed into robots just like Optimus Prime.

"What the heck is going on here?" Mr. Fitzgerald asked after he saw them transform "And who are they?"

"Allow me to introduce them, this here is Jazz."

"This looks like a good place to kick it." Jazz jumped and land on the Watterson's car.

"Did he just jump on our car?" Anais said.

"Lets just ignore that happened." Nicole tried to ignore what happened.

"Our weapon specialist Iron-Hide."

Iron-Hide aimed his arm canons at Gumball and Penny "You feeling lucky punk."

"Easy Iron-Hide you know we don't harm people from earth."

"Just kidding I just wanted to show them my canons." Iron-Hide switched his canons back to his hands.

"I think they are awesome." Gumball said.

"Our medical officer Ratchet."

"According to these calculations the young blue cat wishes to mate the young peanut."

After that Gumball and Penny blushed and backed away.

"And my strongest warrior Bumblebee."

"His vocal processors were damaged in battle I'm stilling working on them." Ratchet said.

"You didn't answer Mr. Fitzgerald's question." Darwin said.

"Yes like I said what's going on here." Mr. Fitzgerald asked again.

"They're in a war, another robot named Megatron was about to kill him, and Gumball saved his life." Penny answered.

Nicole couldn't believe, but she knew that Penny was telling the truth "Gumball you really saved his life."

"Yes I guess." Gumball answered.

"And I owe him a life debt." Optimus said.

"Wait hold on you said that some there's a robot on this planet named Megatron, so where is he." Darwin wondered.

"Well he's got to be looking for something here, but what?" Penny asked.

"Optimus is there something you're not telling us." Nicole wanted to know and thought that Optimus would know.

"About 500 years ago the Decepticons have crossed paths with this planet. The Decepticons and people of earth were at war and the one leading the Decepticons was one of the most powerful of them named Unicron. The people of earth one the battle and killed Unicron and sealed his lifeless body somewhere on earth."

"Well maybe that's what Megatron's after, but why would Megatron go after someone that's already dead?" Darwin asked.

"Well what if this robot named Unicron isn't dead?" Anais asked.

Optimus didn't think about it, but he thought what if he isn't dead. "Then we need to find out were he is now."

I'm not sure if that was another crossover, but it was Unicron from the animated cartoon Transformer Prime. In the next chapter the find one person that they didn't expect would them.