Kaeloo, Stumpy and Quack Quack are playing "alien-hunters", pretending to be on the planet Zorbl. They pretend that Mr. Cat is an alien, but he ruins the game for them and then tells them to go find a different "alien" to play with. Suddenly, an egg-shaped object falls from the sky, bounces off Mr. Cat's head, and lands some distance away, forming a huge crater. The four friends decide to take a look at it. At first, they think it's an egg, but Quack Quack says it isn't. Kaeloo suggests that it may have fallen out of an airplane, and Stumpy thinks it is an alien.
The next day, the buddies are still trying to find out what it is. Kaeloo ascertains that it is not a bomb, and Stumpy suggests that it might be an alien GPS. Kaeloo suggests opening it, so Mr. Cat tries breaking it open with a mallet. Instead, the mallet bounces back onto Mr. Cat and sends him flying. He lands perfectly on his feet and then tries cutting it open with a chainsaw, which doesn't work either. Mr. Cat tests the chainsaw on Quack Quack, and there doesn't seem to be anything wrong with it. Mr. Cat gladly hugs his chainsaw, happy that it isn't broken. Suddenly, the thing floats and emits waves. Kaeloo realizes that it is trying to communicate, so Mr. Cat concludes that it's alive. Stumpy still thinks it is an alien, and he demands that they send it back into space since he thinks it might eat them. Kaeloo refuses, and decides to accept it into their home. Mr. Cat says they should get rid of it since they don't know where it came from, and tries to throw it out of Smileyland, but Quack Quack stops him. Quack Quack and the thing start having fun together.
Mr. Cat threatens to shoot Quack Quack with a bazooka, so Kaeloo tells him to pass the thing to her. She catches the thing with her butt, so Mr. Cat threatens to pull the petals off of a flower if she doesn't give the thing to him. She almost gives it to him, but Stumpy grabs the thing and runs off with it, and Quack Quack and Mr. Cat chase after him. Stumpy passes the thing to Mr. Cat, but Kaeloo transforms and punches him, and the thing is sent flying and Quack Quack catches it. Stumpy trips Quack Quack, grabs the thing from him and jumps off a cliff while holding it (in an attempt to destroy it). Stumpy hits the ground, but Kaeloo rescues the thing from him just in time.
Kaeloo decides that they should accept the thing into their home, but Mr. Cat and Stumpy still believe that it is dangerous, and they start protesting the thing. Mr. Cat whacks it into the sky with a wooden placard, but it returns and hits him several times. Stumpy notices some liquid under the thing and starts to believe that it is radioactive, but Kaeloo denies it, saying the thing is just "marking its territory". Mr. Cat points out that it is not the thing's territory. Kaeloo questions why Mr. Cat is always seeing the bad side of the thing, and she decides that the four of them can vote on whether to keep it or not. Unfortunately, both options get an equal number of votes. The thing starts following Quack Quack around.
While Kaeloo and Quack Quack play leapfrog with the thing, Mr. Cat notes that if the thing is living, it must be able to reproduce, and Smileyland will soon be filled with egg-shaped objects. Kaeloo says it will look like an Easter egg hunt, and she likes the idea. Mr. Cat also points out that it will need to eat... and suggests that it might eat yogurt. He asks Quack Quack whether he would want the thing to eat his yogurt, and Quack Quack throws the thing back into outer space.
Later that evening, the buddies see an announcement about the thing on TV, and it says that whoever finds it gets a reward of one million dollars. Everybody glares at Mr. Cat, who nervously starts laughing.
- Mr. Cat
- Quack Quack
- The scene where Kaeloo catches the thing with her butt is similar to the way she catches the ball in "Let's Play Prison-Ball".