Mojo

Mojo is a little doggie in the Movie continuity family.

"Here lizard lizard lizard..."

Mojo is a chihuahua owned by Sam Witwicky. He is coddled by Sam's mom (much to Sam's chagrin), and apparently has a very weak bladder.

Fiction

Transformers (2007)

Spoiler warning: Plot details follow. Please give an expiry date ({{spoiler|(story)|DATE}}) - either the date of the next episode/issue in the series or 30 days after release, whichever is sooner

When the Autobots went to the Witwicky residence, Mojo made the mistake of releasing lubricant onto Ironhide's foot. Upon discovering this, Ironhide requested permission to terminate the "rodent", but Sam Witwicky told Ironhide that humans love chihuahuas. Ironhide agreed to spare it, though complained that the lubricant would cause rust.

From Teletraan I: The Transformers Wiki, a Wikia wiki.