makeLightningBolt

function makeLightningBolt(a,b)
    local dist = (b.p-a.p).magnitude
    local segments = math.random(math.floor(dist*0.2),math.floor(dist*0.5))
    local boltMdl = Instance.new("Model")
    boltMdl.Name = "LightningBolt"
    local points = {}
    local function slerp(c0,c1,a)
        local c0 = CFrame.new(c0.p) * CFrame.Angles(-math.pi/2,0,0)
        local c1 = CFrame.new(c1.p)
        local startDir = c0.lookVector
        local flightDir = (c1.p-c0.p)
        local totalDist = flightDir.magnitude
        local aheadVec = startDir.unit*totalDist
        return CFrame.new(c0.p + (aheadVec*a)*(1-a)+(flightDir*a)*a)
    end
    local function placeSegment(at)
        local segment = Instance.new("Part",boltMdl)
        segment.Anchored = true
        segment.FormFactor = "Custom"
        segment.Shape = "Ball"
        segment.TopSurface = "Smooth"
        segment.BottomSurface = "Smooth"
        segment.Material = "SmoothPlastic"
        segment.BrickColor = BrickColor.new("New Yeller")
        segment.CFrame = CFrame.new(at.p)
        segment.Size = Vector3.new(2,2,2)
        table.insert(points,segment)
    end
    placeSegment(a)
    for i = 1/segments,1,1/segments do
        local pos = slerp(a,b,i) + Vector3.new(math.random(-5,5),math.random(0,10),math.random(-5,5))
        placeSegment(pos)
    end
    placeSegment(b)
    table.sort(points,function (v1,v2)
        return v1.Position.Y < v2.Position.Y
    end)
    local p
    for _,s in pairs(points) do
        local connector
        if p then
            local off = (s.Position-p.Position)
            connector = p:clone()
            connector.Shape = "Block"
            connector.Size = Vector3.new(2,off.magnitude,2)
            connector.CFrame = CFrame.new(p.Position+(off/2),s.Position) * CFrame.Angles(-math.pi/2,0,0)
            connector.Parent = boltMdl
            Instance.new("CylinderMesh",connector)
        end
        p = s
    end
    boltMdl.Parent = workspace
    return boltMdl
end