Players can get the Jitterbug Egg & Cricket Banjo from the Jitterbug NPC in the Band Room after solving the Mushroom Puzzle Quest, which requires you to press the Mushrooms in the correct sequence, one by one.
The Jitterbug is a secret egg in the Enchanted Forest Biome that requires you to enter a secret room and solve a puzzle. So, if you just unlocked the Secret Tree in the Enchanted Biome and want to solve the area's secrets, here is a complete guide.
How to get into the Enchanted Forest Secret Room in Steal an Egg
Before we go ahead, I assume you can access the sealed Enchanted Tree in the Enchanted Forest Biome. If not, I recommend reading our Steal an Egg Wisp Guide, which will help you locate one, complete its quest, and access the sealed Enchanted Tree.

Once you are inside the Enchanted Forest, you can find the Altar at the center and a walkable platform right next to it. Walk along the platform and reach the top. From there, jump to the left to reach the other platform, as shown in the image above. Now, walk to the end of this platform to find a secret portal. Jump into the wind-like icon to teleport to the Secret Room in the Enchanted Forest Biome.
How to solve the Mushroom Puzzle in the Enchanted Forest Secret Room - Steal an Egg
After jumping inside the Portal, you will find yourself inside a Secret Room with five colored mushrooms in front of you: Red, Blue, Green, Yellow & Purple. Here, you must find the right combination/sequence of mushrooms to press to enter the final secret band room, where you can find the Jitterbug Egg.

To start, press each mushroom and wait for the one that turns everything else black. If it does, you are on the right track. Press that Mushroom again to turn everything black & reveal a pattern that will show you the exact Mushroom you need to press next. Now, press the first Mushroom and the second one from the revealed pattern. Again, everything will go black, revealing another pattern that shows the third Mushroom you must press in the sequence. Repeat this with three Mushrooms, then four, and finally all five Mushrooms.

Once you correctly press all five Mushrooms in the right order, the band room will open right in front of you, where you can find a group of NPCs playing multiple Instruments as a band. Interact with the Jitterbug NPC playing the Banjo to get the Jitterbug Egg & the Cricket Banjo in Steal an Egg.
Remember, this puzzle is different for each player. So, just understand how the puzzle works & replicate it during your gameplay session.
For more on Steal an Egg, check out How to Get Wisp in Steal an Egg or All 5 Vault Part Locations in Steal An Egg - Drone & Lost Parts