Is it possible you were watching Yu-Gi-Oh! Capsule Monsters?
Yugi Muto (romanized as Yugi Mutou in the English-language manga) wakes up after having a strange recurring nightmares about the Pharaoh being captured by an evil monster with glowing red eyes and telling him that why he is having these dreams will become clear when he "plays the game". This time, the Millennium Puzzle starts glowing in response to the dream, bewildering Yugi even further.
Before leaving for school that day, Yugi noticed that his grandfather, Solomon Muto (Sugoroku Mutou in the Japanese versions and English-language manga), had not returned from his "secret expedition" (Yugi was told at the last minute) as his flight was due last night. Yugi is worried about the fact that Solomon is missing.
Meanwhile, there is a new game on the block; the Capsule Monsters board game is the new fad in the Duel Monsters craze, and Yugi has already taken the opportunity to learn the rules of the game. When Joey Wheeler (Jonouchi Katsuya) breaks the news about the trip, Yugi and his friends could not contain their excitement. Yugi, Tristan Taylor (Hiroto Honda), and Téa Gardner (Anzu Mazaki) agree to take Joey's other three tickets.
They find themselves in a forest, with Joey nowhere to be seen. Yugi notices a lot of egg-shaped rocks around, but before they can investigate, some giant cockroaches (Gokibore, a monster from the Volume 6 expansion set) and a giant praying mantis (Kamakiriman, from Volume 3) ambush them. The escapes of Yugi, Tristan, and Téa causes them to have to split up.
Yugi is cornered by the mantis, so the Pharaoh takes over to protect him. He accidentally touches one of the strange egg-shaped rocks whilst jumping, which somehow causes Celtic Guardian to appear. Celtic Guardian attacks the mantis, destroying it.
There is a desert episode, "Eye of the Storm":
They arrive in a desert and find a village, where they are given a pendant and the instructions for the first trial: "Silence the whisper that rides the desert wind". While Solomon stays a safe distance from everyone else, they call forth their monsters and destroy a Medusa Worm, which they initially believed to be the enemy. However, it turns out to be one of many Medusa Worms under the voice's control. Everyone but the Pharaoh is spat on by a worm and is turning to stone. Dark Magician takes the Pharaoh above the storm and the voice sent to confuse them to show him a tornado causing it. The Pharaoh calls Dark Magician back to his capsule and proceeds on foot to reach the voice. However, he isn't strong enough to reach the tornado. He then sees a man wearing a cape and mask, telling him to merge with the Dark Magician to gain the strength needed to pass the trial. Doing so, the Pharaoh becomes the Dark Warrior and flies into the tornado to find the voice is Mystical Sand. Silencing her, the Pharaoh clears the trial and reverses the Medusa Worms' petrification on his friends. The armor takes a toll on the Pharaoh as he is not used to it yet. Yugi takes his place to relieve some of the pain and tells of the man he saw explaining how to use the armor. One of the five shapes on the pendant lights up to signify the victory over this trial, and a doorway comes out of the sand.
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