Razor Tentacles

Attack Attribute – Close Combat.
If the attack is allocated towards an enemy R&F model while the attacker is Engaged with the Flank or Rear Facing of the target’s unit, the attack gains Area Attack (1×5), and its Strength and Armour Penetration are set to half the model’s [the model’s] Strength, respectively Armour Penetration, rounding fractions up. This is done after applying other modifiers.