This must be the oddest tank destroyer ever. Ontos is Greek for The Thing, a fitting name. Armed with six 106mm recoilless rifles, the top four had each a 12.7mm spotting MG fitted to it. The crew had to leave the vehicle to reload the recoilless rifles. I believe it was used by the U.S. Marines in Vietnam. Entered service sometime around 1960 and was retired during the eighties.