Huh?

Cody sang a song for me tonight. It goes:

"It's the Mickey Mouse Clubhouse,
Come inside, it's fun inside.
M-I-C-K-U-I M-O-U-S-E."

Now, I've been to Disneyland. I've met Mickey Mouse. I have not, however, had the privilege of meeting what I can only assume is his brother, Mickui Mouse.