Heres the error: Kurumig is not a valid member of Folder.
I tried everything I could to fix it as in removing Kurumig(a model with parts inside it) from the folder and then deleting the folder, but it still never worked.
game:GetService("ReplicatedStorage").Kurumi.HealEvent.OnServerEvent:Connect(function(plr, m)
local heal = game.Workspace.Extrastuff.Kurumig.Handle:Clone() ------error right here
heal.Parent = game.Workspace
heal:SetPrimaryPartCFrame(plr.Character.RightHand.CFrame)
heal.PrimaryPart.Anchored = false
local JointType = "Weld"
local NewWeld = Instance.new(JointType)
NewWeld.Part0 = plr.Character.RightHand
NewWeld.Part1 = heal.Handle
NewWeld.C0 = CFrame.new();
NewWeld.C1 = heal.Handle.CFrame:toObjectSpace(plr.Character.RightHand.CFrame);
NewWeld.Parent = plr.Character.RightHand
wait(2.834)
heal:Destroy()
end)

8 comments
It means 'Kurumig' isn't a child of 'Extrastuff'. Make sure your object names in the hierarchy are correct and match to the path on that line.
Ok
You’ve misspelled “Kurumig” (Kurumi) in the first line.
do
game.Workspace.Extrastuff:WaitForChild("Kurumig").Handle
if im not wrong it will not error like and it will not work until Kurumig exists
now this actually may yield infinitly so you can use WaitForChild's second argument which probarly prevents it from yielding :WaitForChild("Kurumig", 1)
starmaq i learnt i can use the second parameter, u probs helped me more than you helped Choobu, thank you a lot. I always wondered why my script would give me the Infinity Yield error. Im shocked :D