Cencoroll it's a 27 minute movie made in 2009 by Aniplex and Think Corporation.
Synopsis: Tetsu's pet is a giant blob with eyes and teeth that can change into anything. He communicates with it via telepathy, and it's strong enough to do battle with other giant blob monsters. Tetsu would rather just be left alone... but a strange girl finds his blob monster much more interesting than he anticipated. Unfortunately, so does a rival monster owner.
"Fans who've been following anime for more than a decade tend to complain about the medium's current state of affairs. In Japan as well as America, in industry as well as hobbyist circles, the ones who witnessed the country's animated output peak and slowly fall into decline can at any moment be witnessed bemoaning its latest offerings, featuring tired genre retreads and relentless pandering. While there is certainly no shortage of people who like the new stuff, it's hard to escape that things aren't as inventive in this space as they once were."
Shortly, Cencoroll it's a great history about a giant blob who can transform into any object you can imagine and with that comes a great power for it.
At the beginning, Cencoroll it's a history a little boring because it seems like it's just a random guy who won a blob but it's a real good movie so I really recommend it to you guys.