// if the target at or below 25% health
if(unitTarget->GetHealthPct <= 25)
{
    // Blood in the Water : Rank 1
    if (m_caster->HasSpell(80318))
        // 50% chance
        if(roll_chance_i(50))
            unitTarget->GetAura(80318, m_caster->GetGUID())->RefreshDuration();
    // Blood in the Water : Rank 2
    else if(m_caster->HasSpell(80319))
        unitTarget->GetAura(80318, m_caster->GetGUID())->RefreshDuration();
}