|First Appearance||Gooey Aliens That Control Your Mind|
The Gooey Aliens are small, green mollusk or worm-like aliens that came to Earth on a small meteorite. Their only appearance was in "Gooey Aliens That Control Your Mind".
When Dexter found a Gooey Alien after wishing on a star, he immediately began experimenting on it, but soon enough, this parasitic bacterial lifeform escaped and it split into four bodies which proceeded to take control of Dexter's family. They then catch Dexter and attempt to control him by tossing him in the shower and having the last alien posses him, but Dexter fights and destroys it.
The other three aliens then assume that he was already taken control of and order him to prepare a ship for them to take off, and Dexter pretends to follow their orders and sneaks into his invention room where he decides that the Dexo-Transformer would be best choice for defeating the aliens. He then confronts the aliens and demands that they release Dee Dee and his parents' from their control. They refuse and engage Dexter in battle. Luckily Dexter proves superior and beats them down individually but they decide to combine by climbing on each others shoulders and proceed to beat up Dexter but he is able to gain the upper hand and defeat them. Upon their defeat, they crawl out of the family's brains and attempt to escape but he uses the Dexo-Transforner to stomp them into green goo, finally ending their threat once and for all. Afterwards his parents and Dee Dee are shown in terrible condition from the mind control and Dexter's painful beating, luckily he is able to convince them that they just have the flu and helps to treat their wounds.
- The alien that was killed by Dexter in the shower is referred to by two different names by the other aliens, first being called Cykorg by Dad and later Cyborg by Mom and Dad.
- Dee Dee's alien is simply referred to as Sister Unit.