You are chosen to defend our universe against an imminent cosmic threat. You know nothing about the threat except that it is at least Shuma-Gorath level.
For defense, you're boosted up to Thor-level willpower and durability.
For offense, you get a choice of empowerment. Either:
a) You are infused with the power of the Ultimate Nullifier, with full ability to control and utilize it.
b) You are infused with the power of Pre-Crisis Darkseid's Omega Beams, with full ability to control and utilize them.
After the battle, if you survive and save the universe, you get to keep the power, if you so desire.
Which do you choose?