local ss = game.ServerStorage.models:WaitForChild("sandstorm"):Clone()
local _, position = conv:ray(plr.Character.HumanoidRootPart.Position + Vector3.new(0,5,0), Vector3.new(hit.p.X, plr.Character.HumanoidRootPart.Position.Y + 5, hit.p.Z), 100, game)
ss.Position = plr.Character.HumanoidRootPart.Position + Vector3.new(0,5,0) + plr.Character.HumanoidRootPart.CFrame.lookVector * 5
local tween = conv:tween(ss, {Position = position}, 4)
ss.Parent = workspace
tween:Play()
to get things out of the way: part is massless, not anchored, not collidable. hit is mouse.hit ray is between hrp and mouse with hrp's Y tween is for part, changing it's position to the one obtained by the ray and moved within 4 seconds. I have no clue what is glitching it.
if there are any additional questions I am online for the next few minutes.

6 comments
try anchoring it should fix it
it will not rotate if I anchor it because of rotVelcoity
if i do anchor it, however, it will not glitch anymore.
instead of using RotVelocity maybe you can use CFrame.Angles?
Ahah, you said that right after I did it, I was about to update this post saying that it works well, thanks for your help.
np