This Bible contradiction is from the Skeptic's Annotated Bible.
Matthew 28:2 View context
And, behold, there was a great earthquake: for the angel of the Lord descended from heaven, and came and rolled back the stone from the door, and sat upon it.
A young man
Mark 16:5 View context
And entering into the sepulchre, they saw a young man sitting on the right side, clothed in a long white garment; and they were affrighted.
Luke 24:4 View context
And it came to pass, as they were much perplexed thereabout, behold, two men stood by them in shining garments:
John 20:12 View context
And seeth two angels in white sitting, the one at the head, and the other at the feet, where the body of Jesus had lain.