Challenge Timestamp: 1:06

Unlocks: World Mode Map 2-3

To trigger the challenge, the following requirements have to be fulfilled:

  1. Eto (before first clear) or Luna (after first clear) is your selected Partner.
  2. Eto is Level 6 or higher, or Luna is Level 10 or higher.
  3. (Eto only) You are playing on a difficulty corresponding to your Potential:
    • < 5: Any difficulty chart
    • ≥ 5 and < 10: Present or Future chart only
    • > 10: Future chart only

Upon meeting the above requirements, the challenge automatically begins at 1:06, with Luna appearing and mouthing the phrase "If you can". The floor track then falls out, leaving only her sprite in the background. From this point until 1:28:

  • If your LOST Note count exceeds a certain number (see table below), Luna immediately disappears and the challenge ends.
  • If your LOST Note count is kept under the allowable count:
    • For the first clear, Map 2-3 is unlocked upon clearing the song.
    • For subsequent clears, there is no special reward.

The allowable LOST Note count depends on Eto/Luna's level. Current known values, according to information from the Japanese Wiki and the official Discord server, are:

Partner Level Allowable 'LOST' Notes (Eto) Allowable 'LOST' Notes (Luna)
6 0 -
7 0 -
8 0 -
9 0 -
10 0 0
11 1  ?
12 2  ?
13 3  ?
14 4  ?
15 6  ?
16 8  ?
17 10  ?
18 12  ?
19 15  ?
20 21  ?

Official Sound


Link Player Score Sounds
YouTube higllus 10,001,105 (Max) Finger taps
YouTube Ritxman 10,001,077 Fingernail taps (background noise)
YouTube BengaleeHS 10,001,037 None (Thumb play)
YouTube レイ - Hand clap video


  • Singularity was composed specifically for Arcaea.
  • Singularity was added to Groove Coaster as part of the Arcaea x Groove Coaster collaboration.
    • Singularity in Groove Coaster is titled as "Singularity -Binary Enfold-"., in reference to the pack it is found in, due to GC already having a song titled Singularity.
  • Originally, Memory Forest was planned to be the only song ETIA. contributed, but ETIA. was concerned that it was too shallow, and composed another catchy song. The Arcaea team liked it and ended up using them both [1].
  • While the challenge is active, a dark overlay appears on top of Luna, referencing a black hole (which has a singularity).
  • The note designer's name is likely an alias of Toaster. 東 can be read "tou," and 星 is "star." The コラプサー in 東星※コラプサー translates to "collapsar", a star that has collapsed under its own gravity.
  • The artwork of Singularity and Memory Forest form a complete picture when combined.
    Memory Forest and Singularity

    Combined artwork of Memory Forest and Singularity