This enemy will only appear if the whole ship failed to achieve 100% annihilation rate during the Apos Dorios Emergency.
The more Apos Dorios you defeated during it, the higher this enemy's drop rate will be. (Up to four defeats)
The clock on his body is vulnerable to Mirage status effect, which will cause temporary stun and open up his core. Dealing enough damage to the clock core before he recovers will open up a permanent weak spot for the rest of the battle. You have three chances to expose the core with Mirage before it becomes impossible to re-open. After breaking the clock, he becomes invulnerable to Mirage status.