Raccoon and "Coon" are very different things. Being said Mockoon doesn't actually make that much sense, raccoons aren't known for mocking. Mockingbirds are, perhaps "Mockingbird"? MockBird? I'm sure you'll figure it out.
All mockingbirds are already used :)
I personally like mockoon, sure Raccoon are not known for mocking, but it's the raccoon who mock APIs, why not?
Microsoft is far from creating "micro" softs :)