Name of an animated alien childrens movie?

All I remember is that this little boy finds a lost baby alien (he was green/purple and fuzzy) He tells everyone in town about it but no one believes him. When the other aliens come to get him they are in these huge metal spaceships where i believe landed on a baseball field. They invade the town, in search for the lost baby. They are tiny and fuzzy and nice. Then the town realizes the little boy isn’t crazy. The end. Any help? If it helps, there was all kinds of memorabilia when this movie came out in 2007–2008 PLEASE HELP.