Last digit determines type of attack and grants an additional effect:
0-1 Fire: Bathe the boss in searing heat, causing the next x heroes attacking to deal additional damage. Is cancelled prematurely if any attacks are water based. Does not affect water or fire based bosses.
2-3 Ice: Freezes/slows the boss and prevents (or gives a stacking chance to) prevent the next low rolling hero to die. Chance is reset on this effect saving a hero or the boss being hit by a fire attack. Does not affect ice or fire based bosses. Bosses ignore this effect when enraged.
4-5 Earth: Burden the boss by weighing it down with heavy boulders, guaranteeing that the next x attacks will not miss. Effect ends prematurely if the boss is hit by an ice attack. (Seems a bit weak?) Alternative: You launch a variable sized boulder at the boss, dealing bonus damage which exponentially scales with your damage digits. Earthen or ice bosses are not affected by this.
6-7 Electric: Paralyze the boss with lightning, allowing your allies to exploit its condition: will cause the next x heroes to attack an additional time for the same (or reduced) amount of damage and will cause their attacks to be electric. Is ended prematurely if the boss is hit by an earth attack. Does not affect electric or earthen bosses.
8-9 Water: You launch a surge of water at the boss, dealing a small amount of additional damage. If the next attack is electric, that attack will deal significantly more damage. If the next attack is fire, the attack will not affect the boss. Does not affect water-based bosses, and will kill (or have a chance to kill) the player if cast on a lightning based boss.
It's a bit out there when it comes to suggestions but I hope you take inspiration from it at least!
Last digit determines type of attack and grants an additional effect:
0-1Fire: Bathe the boss in searing heat, causing the nextxheroes attacking to deal additional damage. Is cancelled prematurely if any attacks are water based. Does not affect water or fire based bosses.2-3Ice: Freezes/slows the boss and prevents (or gives a stacking chance to) prevent the next low rolling hero to die. Chance is reset on this effect saving a hero or the boss being hit by a fire attack. Does not affect ice or fire based bosses. Bosses ignore this effect when enraged.4-5Earth: Burden the boss by weighing it down with heavy boulders, guaranteeing that the nextxattacks will not miss. Effect ends prematurely if the boss is hit by an ice attack. (Seems a bit weak?) Alternative: You launch a variable sized boulder at the boss, dealing bonus damage which exponentially scales with your damage digits. Earthen or ice bosses are not affected by this.6-7Electric: Paralyze the boss with lightning, allowing your allies to exploit its condition: will cause the nextxheroes to attack an additional time for the same (or reduced) amount of damage and will cause their attacks to be electric. Is ended prematurely if the boss is hit by an earth attack. Does not affect electric or earthen bosses.8-9Water: You launch a surge of water at the boss, dealing a small amount of additional damage. If the next attack is electric, that attack will deal significantly more damage. If the next attack is fire, the attack will not affect the boss. Does not affect water-based bosses, and will kill (or have a chance to kill) the player if cast on a lightning based boss.It's a bit out there when it comes to suggestions but I hope you take inspiration from it at least!