Enemy 3A, entry points: 080246BC, 0803D7CC

; 0x00, initialisation
; 0x01, thinking
; 0x02, walking
; 0x03, turn around
; 0x04, turning around
; 0x07, standing initialisation
; 0x08, standing
; 0x38, slash attack
; 0x3A, roll attack
; 0x3C, hit wall from roll attack
; 0x3E, cry of pain (shot with missile)
; 0x40, flame attack
; 0x42, dying
; 0x59, start to be born
; 0x5A, be born

Missiles cause 11h frames of invincibility, beams cause 5
Arachnus' EnemyAttachedEnemySlot is Arachnus' shell

In Arachnus' room:
Enemy slot 00: Enemy0E - Static target (for core-x)
Enemy slot 01: Enemy02 - Horizontally moving target
Enemy slot 02: Enemy3A - Arachnus
Enemy slot 03: Enemy15 - Arachnus' shell
Enemy slot 04: Enemy17 - Arachnus' head
Enemy slot 05: Enemy18 - Arachnus' front arm
Enemy slot 06: Enemy19 - Bottom-centre of Arachnus
Enemy slot 07+ are projectile slots
Enemy16 is the slash projectile, Enemy20 is its bottom-centre
Enemy1A is the flame projectile

EnemyOrientation:
0x0020: Set when dying
0x0040: Set when facing right
0x0400: Set when shot
0x0800: Set when flaming
0x2000: Set when rolling
0x8000: Set for no-clip


Understood:
0802381C Arachnus_SetHitboxStanding
08023854 Arachnus_SetFlame
08023894 Arachnus_SetCryOfPain
080238D8 Arachnus_SetDeath
08023950 Arachnus_SetRoll
080239E0 Arachnus_SetSlash
08023A20 Arachnus_SlashAttack
08023B20 Arachnus_RollAttack
08023D18 Arachnus_HitWallFromRollAttack
08023E30 Arachnus_CryOfPain
08023E7C Arachnus_Dying
080241B0 Arachnus_FinishedWalking
0802423C Arachnus_Birth
08024290 Arachnus_Initialisation
080243D4 Arachnus_Thinking
08024404 Arachnus_Walking
08024538 Arachnus_StandingInitialisation
080245CC Arachnus_Standing
08024614 Arachnus_TurnAround
0802464C Arachnus_TurningAround
080248EA Arachnus_FlameAttack

Not understood:
0800270C Sound effect related
08011390 Position related
080119F0 Animation related
08012858 Check through all enemies for orientation 01, collision properties 80 and id r0
08014250 Manipulates the 030000F4 struct
080625C0 Manipulates the 030000F4 struct


Enemy graphic pointer:
083028F4 Walking
08302924 Attached Walking
083029C4 Turning
08302A04 Attached Turning
08302A74 Attached Flame
08302AA4 Slashing/Flame
08302B74 Attached Slashing
08302C44 Standing
08302C6C Attached Standing
08302C94 Attached Rolling
08302CF4 Attached Hit wall from roll attack
08302D54 Cry of pain/Dying
08302D8C Attached Cry of pain/Dying
08302DC4 Attached Finished rolling