Acacia grips her glaive tightly in both hands and uses it as a stabbing weapon against the beast's side, between ribcage and pelvis. Her energy is badly sapped by now, so she's putting her weight behind this move, rather than performing the typical whirling slashing move she typically uses.

If she's successful in penetrating its hide, she'll keep going until the blade part is embedded, and then push on the staff part to cut through its insides, using the staff part as a lever to enhance the force she's using.