This is a bacterial disease.

Mummy Rot [30] 
    Innate Attack (Toxic) 2d [9.6] 
        Malediction (As Regular Spell) [+100%] 
        Based on Activation Roll [+5%] 
        Melee Attack (Reach C, No Parry) [-35%] 
    Innate Attack (Toxic) 0d+1 [20.28] 
        Follow-Up (Malediction-based Toxic Innate Attack) [+100%] 
        Delay (Fixed, 1 Day) [+0%] 
        Cyclic (1 Day Intervals, 179 Cycles) [+1790%] 
            Can be cured by any generic disease cure 
        Symptoms [+60%] 
            Negated Appearance (Transcendent) after 1/3 HP 
        Symptoms [+16%] 
            Appearance (Ugly) after 1/2 HP 
        Symptoms [+12%] 
            Appearance (Monstrous) after 2/3 HP 
    Magical [-10%] 
    Spell Components [-40%] 
        Must say "rot" in Latin 
        Must gesture with hands 
        Must holding something rotted and a piece of mummy wrapping