Kanegon is a Kaiju transformed by Kaneda Kaneo, a boy who is greedy for money, after he was swallowed by a cocoon that makes the sound of money when shaken.
Kanegon’s head is in the shape of a coin purse, while his body is like a Martian. His eyes pop out to the direction of money, his mouth is a zipper of a wallet, his tail is rugged like Godzilla, his thorns on his head are there to make him look strong, and his body shines like coins. Since Kanegon was a human before the transformation, he speaks the same language (Japanese) as humans.
Just like its alias “Coin Monster” suggests, the Kaiju loves money and eats them to keep alive. What he likes the most, are the silver coins from the Olympics.
On his left chest, there is a counter that shows how much money he ate, and the number decreases while he is not eating. If the count goes down to zero, Kanegon dies. The amount to keep him alive is 3520 yen per day.

At first, Kanegon relied on the money given by his friends, but became weak when there are no more coins left and the number of the counter almost reached zero.
When he went to seek help from a fortune teller in order to change him back to human, he is told that the cure is to make Daddy Walrus (the children’s nemesis) do a handstand.
Later, Kanegon chases after Daddy Walrus and drove him into a panic. At the instant when Daddy Walrus tripped on a rock and landed into a handstand, Kanegon was launched into the air and changed back to human.
Since Kanegon is transformed from a boy, neither he has any intention to conquer earth, nor he has any powers to fight with Ultraman. Because of these reasons, he is beloved by many people that are not Kaiju fans, and he gets treated as a character similar to humans even in the spin-off episodes, making him different from other Kaiju.