I'm not a christian, but I grew up in a Baptist household, so I have at least a passing understanding of the Bible. Lemme know if I got any wrong.
If I'm understanding the bible correctly;
God Created heaven and Earth, Including Mankind and Angels
God is all-knowing and all-powerful
Relevant to this discussion, God created Lucifer and all the angels who sided with him.
God made Man in His image, and ordered the angels to serve them.
Lucifer, prideful of his own beauty, and envious of God's (at least perceived) favoritism of Man, and of God's position, started a rebellion in heaven and was/will be cast down into the lake of fire(aka Hell).
lucifer later tempted/took the form of the Serpent in the Garden of Eden and tempted Eve to eat of the Tree of Knowledge.
my conclusion: God, with full knowledge of what lucifer would do/become created him and set him on the path that led to his downfall, and to the Sin of Mankind.
Or to put it more simply; God created Sin through his foreknowledge of what Lucifer would become.
I'm not trying to start a shitstorm here, but this is the logical conclusion that I find myself at.
Any Christian pedes wanna poke holes in this for me?
The boulder question comes from a lack of understanding the difference between omnipotence and sovereignty.
This is going to sound weird, but God is not omnipotent. There are things He can't do. He can't stop being Himself. He can't act contradictory to His own nature. I personally argue that He can't violate the laws of logic because they are an intrinsic part of His being.
What God is is sovereign. That means He has complete control and command over anything else in existence. If He makes a boulder, He can manipulate it however He wishes because He is sovereign. He can't make a boulder that He can't lift, else He would immediately cease to be God.
Again, you're applying human logic to something that supersedes logic... God can do anything even if our human brains can't comprehend it. There are things we will only gain understanding when we are free from the restraints of this mortal coil.