Lost Jungle is the tenth stage in Sonic Heroes. A watery swamp inside a vast jungle, the level contains black frogs that destroys nearby plant life, in contrast to the green frogs seen in Frog Forest. A giant alligator lives in the lowest point of the swamp.
Descending from Frog Forest's canopy, Team Sonic ventures through the depths of the jungle to stop the Egg Fleet to save the world. Team Dark explores the depths of the jungle to pursue Eggman to make him answer for the Shadow Android. In the final steps of the level, Team Sonic and Team Dark must escape a giant alligator that chomps its way to the team. The player must swing on the ivy swings and jump to another until they land on a ledge. Team Rose must escape the jungle to stop the Egg Fleet and impress Sonic. Team Chaotix are tasked to rescue ten Chao.
Team Chaotix mission
For this assignment, Team Chaotix is ordered by their client to protect and collect Chao. The normal mission requires them to collect ten Chao, while the extra mission requires that all twenty Chao in the stage are collected. The location of each Chao are as follows:
|Chao #1||Destroy the Egg Hammer that the player encounters for the first time in the stage to release the spring and the first Chao.|
|Chao #2||After getting the first Chao, run up around the path past the black frog. Just after the Flying Formation Signal is the second Chao.|
|Chao #3||At the ivy swing, turn around and fly up to a Chao on the platform to the left of the previous one the second Chao was in, but higher than it.|
|Chao #4||After proceeding to the path the ivy is leading to, there is a fruit that the player must bounce off on to reach the ledge with three wooden containers. Break the wooden containers to get the Chao.|
|Chao #5||After the first Checkpoint, swing on the ivy, and defeat the Egg Hammer. To the right after the small tunnel on a platform is a Chao.|
|Chao #6||From the fifth Chao, to the left, the sixth Chao is released from a Case as a result of defeating the Egg Hammer.|
|Chao #7||Later on the way after the sixth Chao, after running the loops and bouncing off a spring, check the small mushroom on the left for another Chao.|
|Chao #8||On the next area after the seventh Chao, check the platform on the right, just past the second black frog|
|Chao #9||After landing from the flower ride, and before the player reaches the green frog, back up to the open part of the walls. From the right side, fly straight up to get this cleverly hidden Chao on a sprouting platform.|
|Chao #10||Let the green frog from the previous section see the characters . When the vines and platforms grow out, fly up to get the Chao flying on the growing platform.|
|Chao #11||After going up from the previous section to another circular path, destroy the Solid Flapper near the locked Case to release the Chao inside.|
|Chao #12||Along the way on the circular path, is a lunar surface the player can fly up on top of. Here, two Solid Flappers must be destroyed to release the caged Chao there.|
|Chao #13||After the twelfth Chao, the player should encounter two Egg Hammers inside a tree. Take them out to release the Chao in the Case there.|
|Chao #14||After warping through the Warp Flower inside the tree, grab the Pulley to the left to go down, then jump to the platform. From that platform, fly over to a high platform to get the Chao.|
|Chao #15||From the fourteen Chao, fly down to the bottom of the path and the player should see an Egg Hammer. Destroy it to release the Chao in the nearby Case.|
|Chao #16||From the previous Chao, do not go through the Laser Field Block. Continue on the path from Chao # 15 to the Special Key. Behind the Special Key and near a mushroom is the next Chao.|
|Chao #17||From the previous Chao, return to the Laser Field Block and pass through it by turning invisible. Use the Warp Flower inside to reach a ledge on top and then destroy the two Solid Flappers to release the green frog. After the frog sees the characters and it begins to rain, go to the right and bounce up from the fruit to get the next Chao.|
|Chao #18||On the left side of the same section with the seventeenth Chao, after the frog sees the characters, jump up from the newly grown platform to get another Chao.|
|Chao #19||Bounce off the spring that the green frog was on, to the platform above. Swing from the ivy and destroy the Solid Flapper, then collect the Chao from the Case.|
|Chao #20||The final Chao is hovering above the path in a circular direction on the same platform as the nineteenth Chao.|
The following is a list of requirements to attain a rank for each mission with each team.
|Rank A||Rank B||Rank C||Rank D||Rank E||Mission 1|
|Team Sonic||32,000||28,000||24,000||20,000||<20,000||Venture through the deepest part of the jungle!|
|Team Dark||40,000||35,000||30,000||25,000||<25,000||Explore the deepest part of the jungle!|
|Team Rose||42,000||38,000||32,000||28,000||<28,000||Escape the jungle!|
|Team Chaotix||40,000||36,000||32,000||28,000||<28,000||Rescue 10 Chao!|
|Rank A||Rank B||Rank C||Rank D||Rank E||Mission 2|
|Team Sonic||30,000||28,000||26,000||24,000||<24,000||Get to the goal Ring within 6 minutes!|
|Team Dark||14:00||14:30||15:00||16:00||>16:00||Defeat 100 enemies! (Time in minutes.)|
|Team Rose||3:45||4:30||5:00||7:00||>7:00||Collect 200 Rings! (Time in minutes.)|
|Team Chaotix||32,000||28,000||24,000||18,000||<18,000||Rescue 20 Chao!|
- At some low altitude checkpoints, especially those surrounded by water towards the beginning of the stage, an alligator can be seen in the distance, although, only its head is above water.
- If Tails is left idle, he will say, "I hate that black frog."
- A stage in Sonic Lost World, called Silent Forest, has many similarities to Frog Forest, Lost Jungle, and Tropical Jungle, the latter being from Sonic the Hedgehog (2006).
- The black frogs here do not appear in the previous stage, Frog Forest, despite it being named after frogs.