"You think it's easy keeping a lid on your secret? I've got to think about it every time we're around other people to make sure I don't slip. I've got to remember to say 'meteor rock' instead of 'kryptonite'. And I always got to cover your unexplained exits." - Pete Ross, Asylum.
Clark Kent and Pete Ross were friends from childhood through high school. Pete was the first friend that Clark trusted with his secret. The strain of keeping Clark's secret proved to be too much for Pete, and he moved away to Wichita with his mother at the end of his junior year at Smallville High School.
Clark and Pete became friends in early childhood. When Pete was bullied, Clark came to his defense and they have been best friends ever since, Zero. Clark and Pete often camped outside in their backyards. 
Pete often referred to their childhood friendship, once mentioning that Clark grew sick whenever they went near Greg Arkin's treehouse, near Creekside Foundry, where kryptonite was found in high concentration.
During their freshman year, Pete and Clark were best friends. 
They both tried to join the football team to avoid becoming the Scarecrow, and they worked at the Torch with their mutual friend, Chloe Sullivan. Pete had a crush on Chloe but he believed that she was in love with Clark. 
Pete often joked with Clark about his tendency to be late and the fact that he was very secretive.  In addition, he commented openly about Clark's attraction to Lana Lang. 
Clark and Pete enjoyed playing basketball at the Kent Farm. 
After the tornado hit Smallville, Pete, along with Chloe helped Clark to look for his father after he went missing. During this time, Clark's ship went missing as well. Pete found it in a cornfield after he helped a man in an overturned van and showed Clark. Clark was forced to expose his powers to Pete and tried to apologize for lying to him all the years they had known each other. Pete initially reacted poorly, but eventually understood why Clark had kept his secret. After Pete calmed down, the relationship between the two grew stronger than it had ever been. This was the first time Clark was able to confide fully with anyone but his parents. The two told Clark's parents that Pete knew his secret and at first, his parents were hesitant, but later agreed that it was good for Clark to be able to share his secret with a friend.
Pete later helped Jonathan deal with Clark after he put on a red kryptonite ring. When Clark and Pete went to investigate why Byron Moore's parents kept him a prisoner in his own house, they found him chained in the basement. They tried to get him to leave the house, but once he was in the sun, he underwent a transformation into a feral, super-strong beast and threw Clark and Pete into the air. Pete crashed onto a car and was left with a broken arm. At a welcome-back party held at the Talon for Ryan James, Ryan revealed to Clark that Pete was very stressed out about keeping his secret.
Pete helped Clark investigate Ian Randall when he started dating Lana and Chloe at the same time and it was revealed that Ian could duplicate himself in two. After Whitney seemingly returned to Smallville, Clark discovered it was actually Tina Greer posing as him. Clark told Pete to warn Lana who overheard their conversation. Clark told her to stay with Pete. When she walked off, Pete followed her; it was revealed it was actually Tina after she threw him across the hallway.
When Jonathan Kent was accused of shooting Lionel Luthor, Pete assisted Clark in trying to prove his father's innocence. They went to the Wild Coyote and asked the bartender some questions, but he wasn't any help. When they drove back to town, a masked gunman in a big rig ambushed Clark and Pete. The car ran off the road and Clark used his powers to get them out of the car. Clark threw himself over Pete to shield him from the car's explosion. After finding out the bartender went missing, the two went back to Wild Coyote to find the bartender dead and hidden in a freezer.
After Pete was infected with a parasite in the Kawatche Caves, he began to act strangely. Clark tried to get him some help but Pete wouldn't listen and told Clark's secret to crowd who didn't take him on. Clark x-rayed him to find a parasite in his body but Pete used kryptonite to get away. After Chloe was infected as well, Pete slipped Clark Red K and Clark made out with Chloe in front of Lana. When he went back to normal, Clark stopped Pete and Chloe from driving off a cliff and took them to the hospital. After he was cured, Pete apologized to Clark.
Lex introduced his long lost brother Lucas Luthor to Pete and Clark. After Lex leaves, Lucas played basketball with Pete and Clark but after Lucas hurt himself from elbowing Clark in the chest, Pete took him home. After Martha became seriously ill, it was decided that Clark's ship would be stashed at Pete's shed while the farm was being searched for the cause. However, on the way there, Clark got dizzy and ran the truck off the road. He and Pete managed to push it back on the road as the Disease Control Agency drove passed. Later, Pete became Jonathan and Clark's decoy when they stole the key from the DCA.Clark asked Pete to bring his laptop over to his loft when he got an email from Virgil Swann so he would be able to contact Swann without Chloe or his parents looking over his shoulder.
Pete helped Clark's parents try and find Clark while he was on a crimespree in Metropolis under the influence of a red kryptonite ring as well as help them deal with thier problems because of the situation.
Pete revealed to Clark that he considered it a burden to know Clark's secret, stating how he "always had to remember to say meteor rock instead of kryptonite", and how he had to "cover for his unexplained exits".
Later, Pete started street racing and was told by Jason Dante to purposely throw a race so he wouldn't lose money from bets. When Pete did not throw the race, Dante told him to get back the money he lost in bets. Clark saw that Dante's race cars were stolen from other people. He called the police on Dante, who covered up the evidence that he stole cars. Pete later showed up at the Kent Farm, beaten and bloody. He told Clark that Dante thought that he called the cops and that Dante was affiliated with a deputy so he already knew what was going on. Pete then said that Dante was going to kill him and his family if he didn't pay back the money. Clark asked Lex for the money to pay Dante, but he said "in my experience, money hungry thugs are like stray dogs, and if you feed them once, they'll come back begging for more". Clark stole Lex's Porsche and said it would be a prize for whoever won the race between Dante and Pete. Clark told Pete the plan and that he would fry Dante's engine with heat vision. But Clark overheard Dante talking to one of someone, saying that when Pete's speedometer hit 100 mph the car would detonate. Clark was then knocked out by a kryptonite fuel tank and put into the back of Pete's car. During the race, Clark managed to break the fuel tank, which leaked and caused Dante's car to slip and crash, killing him.
Pete has been captured and tortured by different people, all of them trying to discover Clark's secret. Frank Loder targeted Pete, and nearly beat him to death before Lex intervened. Pete decided that he could no longer stay in Smallville without either being killed or revealing Clark's secret, and moved to Wichita with his mother.
Clark's (assumingly junior) dedication in the yearbook reads, "Wow! Done with another year. But it was definitely another good one. Can't wait for the summer to hang around at Crater lake with PR, CS, and the two LL's. Thanks mom and dad for everything! And of course I'll still be around the farm to lend a hand... See everyone else next year!"
After receiving some criticism from Chloe, Clark mentions how Pete was better at pep talks in relation to his secret, and that he saw the spaceship.
Later on, Clark mentions not being sure on whether to tell Lana his secret, Martha reminds him that Chloe and Pete have accepted him as their friend even knowing about him being an alien.
Pete, now a roadie for One Republic, showed up in Smallville at a concert. He inadvertently chewed kryptonite laced gum, which gave him the power of stretching himself beyond normal capability; he was able to stretch his arms and save Clark's cousin Kara Kent from a piece of scaffolding that would have fallen on her head.
Pete went to visit Clark at the farm and realized a lot had changed since he left, seeing as Chloe, Lana and Lionel all new Clark's secret as well. When he revealed his powers to Clark however, Clark was worried how the kryptonite would affect Pete; but it was already affecting his thinking. Pete wanted to be a hero and wasn't going to hide his powers; he warned Clark that if he tried to stop him, he will expose his secret.
Lex found out about Pete and told him to steal Kara's bracelet. Pete agreed as Chloe was meteor-infected. Pete used his abilities to steal it from Lionel's safe. Clark arrived and tried to reason with him but Pete used Green Kryptonite to weaken him and left. After Lionel freed him from it's affects, Clark went to save Pete who was being tortured by Lex's men. Clark rescued him before there was anymore serious damage.
Pete later apologized to Clark for blaming him on how his life turned out and said it was time for him to make a change and find another way to save the world.
When discussing how dangerous knowledge of his secret is, Clark reminded Chloe about those in his life who died or left him including Pete.
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