Iguana is one of Matt Walmart's reptiles. He has a grudge against Matt for various reasons. One of which being Matt: Retreive arms from Iguana. He will not tolerate swearing and thus blocks every swear word with a splat.  Iguana is the only reptile not to be named Francisco Armando Hernandez III, mostly because of this .

Iguana has the most personalty out of any of the reptiles, and certainly seems to be the only one with a brain.