Ballista
If the equipped monster attacks a face-down Defense Position monster, it gains 1500 ATK during damage calculation only.
local s, id, o = GetID()
function s.initial_effect(c)
	aux.AddEquipSpellEffect(c, true, true, Card.IsFaceup, nil)
	--atk up
	local e2 = Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_EQUIP)
	e2:SetCode(EFFECT_UPDATE_ATTACK)
	e2:SetCondition(s.atkcon)
	e2:SetValue(1500)
	c:RegisterEffect(e2)
end
function s.atkcon(e)
	if Duel.GetCurrentPhase() ~= PHASE_DAMAGE_CAL then
		return false
	end
	local eqc = e:GetHandler():GetEquipTarget()
	local a = Duel.GetAttacker()
	local d = Duel.GetAttackTarget()
	return d and a == eqc and d:GetBattlePosition() == POS_FACEDOWN_DEFENSE
end


Ballista
If the equipped monster attacks a face-down Defense Position monster, it gains 1500 ATK during damage calculation only.
-- Ballista
local s, id, o = GetID()
function s.initial_effect(c)
	aux.AddEquipSpellEffect(c, true, true, Card.IsFaceup, nil)
	--atk up
	local e2 = Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_EQUIP)
	e2:SetCode(EFFECT_UPDATE_ATTACK)
	e2:SetCondition(s.atkcon)
	e2:SetValue(1500)
	c:RegisterEffect(e2)
end
function s.atkcon(e)
	if Duel.GetCurrentPhase() ~= PHASE_DAMAGE_CAL then
		return false
	end
	local eqc = e:GetHandler():GetEquipTarget()
	local a = Duel.GetAttacker()
	local d = Duel.GetAttackTarget()
	return d and a == eqc and d:GetBattlePosition() == POS_FACEDOWN_DEFENSE
end

