pirahna : piranha, Parana, Purina, prawn, Oriana, Rana, Ariana, Briana, Iran, prawns, Pren, Zorana, paranoia, paring, pron
Some of those are funny...but I'm very bothered by the fact that "pron" (usually typed "pr0n", leet-speak for "porn") is accepted enough to be listed as a PROPER spelling fro something.