Geometry Dash Phobos is an Extreme Demon level in the game, created through a collaboration between GMTSean and verified by KrmaL on May 12, 2016. Initially, the level was considered nearly impossible and was hack-verified by Tygrysek on November 25, 2015. However, it was later made easier. Although the nerfed version is still difficult, the original unnerfed version is slightly easier than Sonic Wave but harder than Bloodbath. For a long time, the unnerfed version of Geometry Dash Phobos was believed to be impossible.
On May 12, 2016, KrmaL (previously known as Krazyman50) legitimately verified Geometry Dash Phobos on a 60Hz frequency. The level was re-uploaded under his account and regained its Demon rating. Surv completed the level on May 23, 2016, followed by Atomic on August 18, 2016. Since then, several other players have beaten it, including SoulsTRK, Sunix, BlassCFB, and Skullo.
A highly challenging remake of the unnerfed version called Deimos was created by EndLevel and officially verified by npesta on February 17, 2019. It features significant difficulty enhancements. Additionally, a sequel named Deimos was created in version 2.1 by ItsHybrid and verified by Doggie on August 5, 2023.
0-4% (KoBaZz): The level starts with a simple but confusing section where you control a mini-cube. It requires precise timing and has fake orbs and gravity portals. This part is considered the easiest.
4-8% (Tandrii) (a.k.a. Honeyb): The background and ground darken, and you enter a moderately difficult wave section. It has a similar style to Acropolis and requires precise timing. There's a cube part that quickly transitions into a challenging mini-wave segment with obstacles. You need to go under a sawblade to progress.
8-13% (TechneT): Another cube part, similar to KoBaZz's section, follows. It's slightly harder and requires even more precise timing. The design is similar to Steam Chamber by Darnoc and Mechanic Megaforce, another level by TechneT.
13-19% (GMTSean): This part is a confusing UFO sequence with jump orbs. Precise timing and jumps are needed to pass through. This section was toned down (nerfed) because it was almost impossible to beat.
19-26% (Jobet): A half-speed ship sequence follows, with tight spaces and various gravity changes. It's a tricky part with mirror portals and speed and gravity portals that can confuse inexperienced players.
26-33% (NiTro451) (formerly Eduard0): This section is a challenging wave segment with tight spaces, sawblades, and double-speed.
33-39% (iBlade): You enter a ball sequence that requires precise timing and jumps, especially when switching gravity at the end of platforms to avoid spikes. It's followed by a tight wave segment with gravity portals. iBlade's name appears letter by letter during this segment.
39-45% (Palery): This part is a mini-ship sequence with multiple speed changes designed to disorient the player. It's followed by a triple-speed mini-wave with invisible slopes, which is relatively simpler compared to other parts of the level.
45-49% (Smokes): The level's color changes to green. You enter a mini-ball segment that requires precise timing, with many fake lines and invisible platforms. Then there's a UFO segment with a purple background.
49-54% (Jo2000): You encounter a half-speed ship sequence with orbs, gravity portals, and tight spaces. In the middle, you become a mini version of the ship and complete that part. The section ends with a hard triple-speed wave segment featuring a gravity switch.
54-58% (DreamEater): This part mainly involves a straight flying segment with size and gravity portals scattered everywhere. It also has timing-based orbs that need to be hit correctly. There's a brief wave section toward the end.
58-61% (Tygrysek): This is a triple-speed dual ship sequence that briefly switches to half-speed in the middle.
61-63% (Iqrar99): Next, you encounter a short but difficult half-speed mini-UFO/mini-ball mixed dual segment, similar to the one in Ditched Machine.
63-68% (Skitten): This section is a normal-speed ship sequence with clusters of sawblades. It has many gravity portals and yellow orbs that require precise timing. The ship suddenly changes to a UFO with more gravity portals and orbs.
68-72% (Kubs0n): In the older version of the level, this part started with a mini-ship sequence, followed by a mini-wave section with tight spaces, tricky timings, and hard-to-notice objects. It resembles one part from Sonic Wave. In the nerfed version, the player controls a regular wave instead of a mini-wave.
72-75% (Andromeda): This part resembles Andromeda's collaboration level, Lunatic Doom Machine. It consists of crosses, an upside-down half-speed ship sequence, and a straight flying section in a narrow path. Originally, the ship was mini, but it became a normal ship due to Kubs0n's part being nerfed.
75-79% (Caernarvon725): This part was created after Update 2.0. It features a ball sequence with tight spaces, speed- and size-changing portals, and precise timing. The name "Caernarvon" can be seen toward the end.
79-82% (Razur): Razur's name appears, and you enter a short but challenging UFO part with moving obstacles that require somewhat difficult timings.
82-90% (WOOGI1411): You encounter a ship sequence, followed by a short ball segment, and then another ship sequence. There's a rotating group of sawblades that you need to dodge using a move trigger. This part requires a significant amount of straight flying and is quite difficult. There's a brief robot part that appears momentarily. After that, there's a quick triple-speed cube segment. A "Take a Break" text appears (originating from Challenge Accepted) before transitioning to the next part.
90-95% (TamaN): This part features a mini-wave section with tricky timings and tight spaces. The wave switches to a mini-robot and then back to a mini-wave. It requires precision and quick reflexes.
98-100% (Krazyman50): This is the final part of the level and is considered the hardest. It starts with a mini-cube section with tight spaces and confusing gravity portals. Then it transitions to a mini-ship sequence with speed changes and gravity portals. The ship section ends with a tight wave segment with sawblades and gravity changes. Finally, it transitions to a mini-ball section with precise timing and a gravity switch to avoid spikes. The level ends with a victory message.