Commemorating... what?

Enemies

1. HPDamageDPSRange
2. 
   The FaceBoss100%

   At 3.3s

   99,9992,000220340
3. 
   Hippoe200%

   At 6.7s

   2,00020090160
4. 
   Metal Hippoe100%

   At 13.3s

   80200333160
5. 
   Hippoe200%

   At 26.7s

   2,00020090160
6. 
   Hippoe200%

   At 30s

   2,00020090160
7. 
   Hippoe200%

   At 36.7s

   2,00020090160
8. 
   Metal Hippoe100%

   At 50s

   80200333160
9. 
   Metal Hippoe100%

   At 53.3s

   80200333160
10. 
    Hippoe200%

    At 66.7s, Unlimited, every 20–40s

    2,00020090160

Enemy	Spawns	HP	Damage	Range	Details
The FaceBoss100%	At 3.3s	99,999	2,000220 DPS	340
Hippoe200%	At 6.7s	2,000	20090 DPS	160
Metal Hippoe100%	At 13.3s	80	200333 DPS	160
Hippoe200%	At 26.7s	2,000	20090 DPS	160
Hippoe200%	At 30s	2,000	20090 DPS	160
Hippoe200%	At 36.7s	2,000	20090 DPS	160
Metal Hippoe100%	At 50s	80	200333 DPS	160
Metal Hippoe100%	At 53.3s	80	200333 DPS	160
Hippoe200%	At 66.7sUnlimited, every 20–40s	2,000	20090 DPS	160

Like most stages, this one also sends a Ms. Sign if the battle goes past 15 minutes.