The answer to both of Big D's questions is 'yes, but he/it will then be finite in power'.

It's like the 'there is a travelling projectile that can smash through any surface and a shield capable of blocking any projectile. If the two were to collide, what would happen?'

The question itself is flawed as it asserts that there exists an object whose existence would negate the existence of the other object.

Likewise the nice wordplay: I am taller than you who is taller than me. Who is taller?

The sentence is english but makes no sense as it asserts ideas which are in contradiction with the other. Likewise to the God paradox, such a rock cannot exist in tandem with an omnipotent God.

Though all these problems assumes that time exists, is linear, and that even an omnipotent being/power is subject to it.