When an unstoppable force meets an immovable object.

The force is redirected.

Quoting Posty McPostface

What happens?

Is this a philosophical question? It has been tested empirically.

Ask Trump.

All of the observers in the stands will be vaporized.

The unstoppable force is stopped, and the immovable object moves.

This, by the way, is an unthinkable thought.

Neither exist.

There's no possible world where both an unstoppable force and an immovable object exists. They are both co-impossible.

It is impossible to have two distinct absolutes. The immovable object and the irresistible force are one and the same.

I agree with unenlightened and Purple Pond. There can't be an unstoppable force if there is an unmovable object, and there cannot be an unmovable object, if there is an unstoppable force. The question makes no sense.

What if the unstoppable force and the unmovable object combines to become an unstoppable object that moves with force?

The object itself might be 'unmovable' but the space around it would be susceptible to pressure from an 'unstoppable' force.

Movement is merely about 'perception', and the 'idea' that an object is "unmovable' is based on the 'perception' of the suggested 'application' of force. 'perception' is a factor.