I created this application to give myself and my linkshell (guild) members an edge when it came to claiming HNM's (Highly Notorious Monsters) in Final Fantasy XI. With this program you can make all of the player models, monsters that spawn in certain areas, and player's pets become invisible with one click of the mouse! This really came in handy to lower lag from player models rendering and to reduce the chance to attacking the wrong monster when the HNM spawned.
The way this program works is before you enter a desired zone where you want to make player/monsters/pets invisible, you select what you want to make invisible in the program and hit the "invis." button. While you are zoning and FFXI is "downloading data..." it will load the newly swapped .dat files and make your selection invisible! To return everything to defaults, just hit restore defaults and zone again.
I no longer play FFXI so I do not have any plans to update this program.