Does anybody know which Chapter:Verse of Genesis contains the story of some guy who was compelled to impregnate his widowed sister-in-law, but then withdrew at the last minute and God killed him for it?

I'd look myself, but I don't have access to a bible at the moment.

Thanks.

That sounds like a cool story.

Search on Google for it.
Google is great for finding things.

It's the story of Onan. Onan was killed because he failed to follow God's law and because he 'spilled his seed onto the ground'.

Nox

Anyone who refers to it as "seed" weird me out.

Nox I think we have something in common. Well it is a sin to spill 'seed'(sperm) into the ground. Hence masterbation. And God killing him shows how serious about it he is and this guy in Genesis also went against God's will for them to have a child.