This is a safety tool.
I am sure the inventor of the spell said this:
I have invented a new spell: flame shere
It is absolutely safe. When you cast the spell and you do not move it, it will come back to you and hit you until you fail concentration or you are dead.
This makes sure it does not run away and burns down the next village.
Same for spike groth. Just walk through it until it breaks your concentration or knocks you out.
Larian, please give us a button to stop concentration.

Prof. Dr. Dr. Mad S. Tist

World leading expert of artificial stupidity.
Because there are too many people who work on artificial intelligence already