Cows Come to our House

Gavin had a REALLY bad dream Monday nite. He even ran out of bed, RAN up the stairs and into bed with us. He NEVER gets out of bed when he has a bad dream, just cries out. He was mumbling something about a cow coming to our house. I said, honey there is no cow coming to our house, they live on farms. We couldn't keep one here, there's not enough room. About 2 hours later I ask him if he is ready to go back to bed, he said uh. I said do you need to go potty, yes he did. So I took him downstairs and the whole time his eyes were HUGE looking out for this cow! I again reassured him that there was NO cow coming! Got him back to bed, and he slept in til 8:15, which is LATE for him! ALLLLL day Tuesday he kept saying that there was a cow coming to our house and going to knock on our door. I tried EVERYTHING to get him to understand that that would NOT happen! Luckily got him to bed that nite and no bad dreams! :O) But Wednesday morning he asked about it twice, then not again. I am STILL trying to figure out where this "cow coming and knocking on the door" came from! He has not watched any cow movies lately, or anything that had a cow in it!
So if he tells you that a cow was coming to our house, you'll somewhat understand where it came from. But TRY to get him to stop asking, and explain to him, that's just NOT going to happen! :O)