The Morning Star in Isaiah 14:12 is Sitting on the moon

Isaiah 14:12 (KJV) "How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations!"

However, here's how the verse appears in some modern translations:

Isaiah 14:12 (NIV) "How you have fallen from heaven, O morning star, son of the dawn! You have been cast down to the earth, you who once laid low the nations!"

Isaiah 14:12 (NASB) "How you have fallen from heaven, O star of the morning, son of the dawn! You have been cut down to the earth, You who have weakened the nations!"

Isaiah 14:12 (Young's Literal Translation) "How hast thou fallen from the heavens, O shining one, son of the dawn! Thou hast been cut down to earth, O weakener of nations."

The fall of Lucifer, from
Paradise Lost by John Milton

Some KJV-only supporters have pointed to Isaiah 14:12 in the other English versions, and accuse them of a great, even heretical, mistranslation error. Some even suggest that these versions are suggesting that Christ and Satan are one in the same, and that Satan himself is responsible for inspiring these translations! This extreme view is because of where, in the KJV, Christ calls himself the "morning star" in Revelation 22:16:

Revelation 22:16 (KJV) "I Jesus have sent mine angel to testify unto you these things in the churches. I am the root and the offspring of David, and the bright and morning star."

Revelation 22:16 (NIV) "I, Jesus, have sent my angel to give you this testimony for the churches. I am the Root and the Offspring of David, and the bright Morning Star."