|Season 1, Episode 17|
|Japanese Title|| ハム!カンバック|
Ham! Come Back
|Episode 16: Great Battle at Sea||Episode 18: Our Friend Henger Forever|
Underground Adventure is the seventeenth episode of Season 1 of the Monster Rancher anime series. It aired in Japan on August 7, 1999.
Genki and the gang reach land and head for a cave that might take them to the other side of the cliff. Tiger and Hare's rivalry finally comes to a head, when the gang gets lost in an underground labyrinth. Hurt by Tiger's harsh words, Hare takes off on his own. But in the end, Hare's wits may be the only thing that can save them from the mind games of a Joker.
The group comes to a mountain range, and Tiger suggests that they travel over it. Hare argues that doing so would drain them financially, so he suggests going around the mountain. Tiger says that he is tired of Hare always being concerned about money, and the two are on the brink of fighting.
Mocchi now finds a cave in the mountain, and Golem super-sizes the entrance so they can all fit in. They get lost in no time, especially when Gali sends Joker into the cave to confuse them. Joker avalanches the stalagmites and traps them in a maze, and Tiger blames Hare. Hare has had enough, and leaves.
To make matters worse, Joker sends a fireball after the group when they are trying to find a way out. But Golem shatters it easily, because it's an illusion. Joker then reveals himself, and Tiger knows he can easily defeat him. Joker makes an illusion of Moo and Tiger is entranced to fighting him. He also summons an illusion on Golem that he is drowning, Holly is running from falling daggers that resemble her father's, and Suezo, Mocchi, and Genki are bounded by chains.
Just when Joker decides to finish off Genki first, Hare finds them and attacks Joker. They are all freed from their illusions, but Joker's final trick up his sleeve is the squadron of Evil Hares. The Searchers easily take most of them out, and Joker goes for Tiger while he is too busy fighting to defend himself.
Hare rushes to push Tiger out of the way, and he starts glowing. He uses the Dragon Kick, and sends Joker flying into the roof of the cave, causing a cave-in. The Searchers escape, but the Evil Hares are not so lucky. Tiger and Hare finally resolve their dispute, but they continue to squabble over money matters.
- In the English version, Suezo's illusion of being surrounded by females was edited out, possibly due to the Playboy bunny outfits that the Lookers wore.