Why won't this mesh rotate? and why does the instance spawn ABOVE the forcefield?

I am creating a forcefield tool and i'm still tweaking all of the parts, but i'm stumped at a part. Whenever this mesh spawns, the object doesn't rotate continually like i want it to. Also, when the mesh spawns, it spawns above the Force Field instead of inside it, next to the humanoid like I want it too. I'm assuming that's a collision issue, but i still don't know how to fix it. Here is the code:

local tool = script.Parent

local health = false

x = math.random(25, 50)
y = math.random(25, 50)

a = 0

b = 0

local debounce = false

local character = game:GetService('Players').LocalPlayer
local player = character.Character or character.CharacterAdded:wait()

tool.Equipped:connect(function(mouse)
    mouse.KeyDown:connect(function(key)
        if key == "q" and debounce == false then
	debounce = true
	print("ForceField")
	local ForceField = Instance.new("Part", player)
	ForceField.BrickColor = BrickColor.new("Deep blue")
	ForceField.Transparency = 0.7
	ForceField.CanCollide = false
	ForceField.Anchored = true
	ForceField.Shape = Enum.PartType.Ball
	ForceField.Size = Vector3.new(25,25,25)
	ForceField.BottomSurface = Enum.SurfaceType.Smooth
	ForceField.TopSurface = Enum.SurfaceType.Smooth
	ForceField.Position = player.Torso.Position
	ForceField.Parent = game.Workspace
	
	ForceField.Touched:connect(function(hit)
		local humanoid = hit.Parent:findFirstChild("Humanoid")
		if not hit:IsDescendantOf(player) and health == false then
			health = true
			humanoid.Health = humanoid.Health -3
			print ("DEATH TO THE HEATHENS")
			health = false
		else
			print("Hi Me ;)")
		end
	end)
	tool.Equipped:connect(function(mouse)
    mouse.KeyDown:connect(function(key)
        if key == "q" and debounce == false then
	local explosion = Instance.new("Part", player)
	local m = Instance.new("SpecialMesh")
	m.Parent = explosion
	m.MeshType = "FileMesh"
	m.MeshId = "http://www.roblox.com/asset/?id=20329976"
	m.TextureId = "http://www.roblox.com/asset?id=39251676"
	m.Scale = Vector3.new(8,8,8)
	explosion.Size = Vector3.new(8,8,8)
	explosion.Anchored = true
	explosion.CanCollide = false
	explosion.Transparency = 0
	repeat
		explosion.Rotation = Vector3.new(0,a,0)
		wait(.1)
		a = a+3
	until
	b == 0
	explosion.Position = player.Torso.Position
	explosion.Parent = game.Workspace
	wait(2)
	explosion:remove()
	
end
end)
end)
	wait(2)
	ForceField:remove()
	debounce = false
	end
end)
end)

it's quite a lot of code, but it's just spawning two different parts next to your character and damages anyone else that touches it, lol. Thanks in advance!

When you set a part's position, it will not allow the part to clip through other parts, so it will automatically move it upwards and reset the rotation until it's not clipping any other parts.

The way to get around this would be to use CFrame

You will need to do something along these lines:

Part.CFrame = CFrame.new(
	XPosition,
	YPosition,
	ZPosition
) *CFrame.Angles(
	math.rad(XRotation),
	math.rad(YRotation),
	math.rad(ZRotation)
)

Here is an article on CFraming if you wish to read up on it more.

Hope this helps!