“Be of good cheer, it is I"
“But when they (the disciples) saw him (Jesus) walking upon the sea, (but) they supposed it had been a spirit (ghost), and cried out: 50 For they all saw him, and were troubled. And immediately he talked with them, and saith unto them, Be of good cheer: it is I; be not afraid. (Mark 6:49-50 (KJV)
They thought they had seen a ghost!