This plate has multiple meanings.
1. The Isuzu Vehicross looks like a warthog (the animal), it has "tusks" in the grill, mirrors that look like floppy ears, and the bumps on the headlights look like the horns above the eyes of a warthog (and are actually called "horns lights" by VX enthusiests)
2. The Vehicross looks slightly (it's a stretch) like the Warthog vehicle in the Halo video game (at least more so than any other production vehicle). Also the Vehicross was Isuzu's "Halo" car. While not a Halo fan I am a gamer so it seemed appropriate.