She is mentioned when Paintbrush thinks she may be able to build a rocket. Lightbulb and Paintbrush soon start to bicker, then Lightbulb finally agrees to let Test Tube build the rocket. She quickly builds the rocket, much to Lightbulb's shock. It is revealed at the end that her team only brought an egg back from space, and is once again up for elimination.
Test Tube is astounded that Yin-Yang discovered her lab, and quickly justifies the "Science Rules" to him to attempt the prevention of the rules being broken. However, Yin-Yang immediately begins breaking the first rule, "Don't touch anything", by reaching for and poking an electrical tube. As Test Tube panics and starts to scold Yin-Yang, Yin explains that if he was not attached to Yang, he wouldn't do anything wrong. Test Tube then showcases her newest experiment; Experiment 626, created exactly for the purpose of separating Yin and Yang, as so they would not argue any more for the benefit of Team Bright Lights.
After moments of arguing between the two, Test Tube shoves the experiment into Yin-Yang's mouth, causing them to float into the air, begin glowing, and eventually split in two after a flash of light. As Test Tube is happy at succeeding with her experiment, the newly separated Yang runs over to the electrical tube he touched earlier, breaks the glass part, then jumps and smashes through the roof.
Paintbrush calls to the attention of her and Yin-Yang's absences at elimination. Test Tube and Yin then appear moments later, with the latter revealing Test Tube separated her and Yang. Paintbrush questions the whereabouts of the darker half, and Yin admits that they tried to find him after he had ran away.
Test Tube is safe with 119 votes at elimination, then she is chosen to swim during the challenge against Soap. While Soap is hesitant to get in the pool, Test Tube quickly jumps in with ease with a cork covering her top so that none of her solution gets in the water. She slightly teases Soap warning her about numerous germs, which frightens Soap, who interrupts Test Tube, who then replies, "Oh, thought you'd like to know." Before swimming on, Knife complains for Soap to hurry up as Test Tube eventually makes it out of the water.
In Cooking for the Grater Good, Test Tube is first seen laughing at the picture of Knife and Dora that Trophy is displaying, and she is also seen at the other teams elimination, reminding MePad about how contact with poison ivy can cause blisters. She is, along with almost every other contestant, happy when MePhone4 announces a Pizza Party instead of a challenge.
She hugs Paintbrush (and cheers) once Paintbrush elects him/herself as leader. She fawns over Lightbulb's cookie Pizza. She reminds everyone what germs are contained within a Pizza, to which Knife then tells her to shut up about, making her mutter nervously. Her team wins the challenge.
During the challenge, Fan passes the soccer-ball to Test Tube, but then Soap quickly steals it, to which Test Tube nervously mutters. When MePhone4 orders that Knife go sit on the bleachers due to a penalty and Soap, Balloon, and Microphone "Ooh" at him, Test Tube appears from the left with another nervous mutter. While Microphone is yelling at Dough and Team Bright Lights makes a goal, Test Tube is seen cheering with her team. Shortly afterwards, she is seen annoyed by Yang's evil laughter.
When MePhone4 allows the members of The Bright Lights (minus Yin-Yang and Paintbrush) to have five penalty shots against Baseball, Test Tube calculates that the team must pass at least four of the five shots to win. Just like the other four shots, however, her's is blocked by Baseball. She and rest of her team is put up for elimination.
In Let 'Er R.I.P., she is seen with Fan while looking through her telescope. She and Fan also trick MePhone5S and MePhone5C to fall down a cliff, which leads to the two phone's deaths. She also tells MePhone4 that it isn't Halloween during the elimination.
At the haunted house, she and Fan briefly discuss why Lightbulb and Paintbrush fight all the time, and she states that she thought Paintbrush was a girl, which makes Fan say "Oh, don't get me started on that one". She and Fan then notice the flying objects in the house and assume that they're just string then possibly a black hole. Bow comes out of a broken chair and calls them lame, then Fan runs out of the house screaming. She states that she thinks seeing a ghost is fascinating until she realizes she was wrong about ghosts and suddenly becomes paranoid, believing that she could possibly be wrong about everything else she had studied. She then starts screaming out of stress and suddenly shatters, which leaves Bow somewhat fazed.
In Everything's A-OJ Test Tube agrees with Fan that her team will win anyhow. Later on while the contestants are singing, she is seen with Fan doing her "science" stuff. When Paintbrush gets mad, in the corner she makes a face.
In Theft and Battery Test Tube says "I'm prepared for any technology disaster, with my trusty bag of rice!" She then throws the rice onto MePhone4 who malfunctioned due to low battery. She then tries again and it still doesn't work. She turns around and gets mad at Fan who thinks that everything on the internet is true. Later on the Bright Lights team is seen in a balloon. Test Tube gets excited about going to Meeple Headquarters and starts jumping about. Paintbrush starts off in an okay mood before losing his/her temper towards the two. In the headquarters, Test Tube told Steve Cobs that Fan said no to giving his egg away. After all the commotion happened, she is seen fixing MePhone4.
In Rain On Your Charade, Test Tube is barely seen as she has essentially no lines.
In Mazed and Confused, Test Tube agrees to take care of Fan's egg. She later is walking through the maze alone and talking to her egg about how nice it was of Fan to trust her but then ice and fire are blasted at her but she was able to dodge them. After everyone is out of the maze except her and Knife, she hears Microphone's voice and follows it. As she runs, fire is continuously blasted at her. She catches up with Knife and both of them jump out of the maze, landing at the same time. She then is seen at the Spoiled Lemon concert.
In Kick the Bucket, during the challenge she got the job of getting the bucket from Lightbulb and passing it to Fan. Then when Fan is talking to Paintbrush, Test Tube is telling him to take it, getting more frustrated every time he doesn't take it. During Afterlife in the Limelight, she is seen throwing and dropping the bucket to Fan and both of them laughing it off. Test Tube runs back to Lightbulb who accidentally throws her into the water and all she reappears with all her contents emptied. She is then the bucket, being carried by Lightbulb and Fan to the tank. She's later holding a ball, still dizzy. At the last moment she becomes conscious again and throws the ball at the goal and scores.
In Alternate Reality Show, Test Tube is at her lab and takes the temporary paralyzer Microphone returns. She gets angry when Lightbulb comes in, presumably because objects keep on coming into her secret lab. After Lightbulb misuses the time machine, they are both sucked into a portal. Test Tube and Lightbulb appear in episode 1 of Inanimate Insanity.
Test Tube gives Lightbulb a talk about how to not interfere with the past after she tries to talk to Paintbrush. She walks around and then freaks out that she broke a twig and tries to fix it. After Lightbulb messes up the past, she goes back to the present only to find out that it's completely different and doesn't seem to like the Inanimate Infinity contestants and tries to fix her time machine. Test Tube is then chosen to be eliminated by Pepper and Salt and Lightbulb steps in saving her. They both go back to episode 1 and fix what had been change and return to the contest. Test Tube, with 10 seconds to draw something, draws a moon but was never scored since her painting was burned. Later, she is talking with Fan, probably about what happened, on top of the vending machine that leads to her lab. At elimination, Test Tube voted Baseball and didn't get any votes and waves goodbye to Paintbrush as they walk into the elimination portal.