function lowHpAnimation(self)

    local a = self:GetAlpha()
    if self.anim_alpha_dest == nil then
        self.anim_alpha_dest = "down"
    end

    if a >= i_alpha and self.anim_alpha_dest == "up" then
        self.anim_alpha_dest = "down"
    end

    if a <= i_anim_alpha_lower and self.anim_alpha_dest == "down" then
        self.anim_alpha_dest = "up"
    end

    if self.anim_alpha_dest == "down" then
        self:SetAlpha(a-i_anim_alpha_speed)
    end
    if self.anim_alpha_dest == "up" then
        self:SetAlpha(a+i_anim_alpha_speed)
        self:SetAlpha(a+i_anim_alpha_speed)
    end
end