How would i know what block is in front of another part?

I'm making sort of a "special attack". When you mine one of the grass blocks than the one in front of that grass block should be removed as well.

Everything works right now but it searches through hundreds of models to look for one model that has the magnitude of 8 to the real grass you are mining so it lags a lot.

Is there any better way to make this function better and not as laggy.

Modulescript:

local Attacks = {}

function Attacks:SpecialAttack(player, self, zone)	
	local Tool = player:WaitForChild("Tool")
	
	local k = 0
	
	local ChosenGrass
	local ChosenIndex
	
	if Tool.Value == "Trident" then
		for i,v in pairs(workspace.Harvestable.Grass[zone.Name]:GetChildren()) do
			ChosenIndex = math.random(1, #workspace.Harvestable.Grass[zone.Name]:GetChildren())
			ChosenGrass = workspace.Harvestable.Grass[zone.Name]:GetChildren()[ChosenIndex]
			if (ChosenGrass.PrimaryPart) and ChosenGrass ~= self.NPC and (ChosenGrass.PrimaryPart.Position - self.NPC.PrimaryPart.Position).magnitude < 8 then
				return ChosenGrass
			end
		end
	end
end

return Attacks