Beastboss are a special type of Ork Warboss who has decided to go full native and lead a Beast Snagga clan. Like their 'modern' contemporaries, Beastboss appear when enough Beast Snaggas come together to form an army of their own, or at least start asserting dominance over mobs of ‘lesser’ Boyz.
Decked in the spoils of their greatest kills and rippling with muscle, scar tissue, and bad attitude, Beastbosses lead from the front lines and look for the biggest, meanest prey they can find to bring down with their laws.
In a possible case of GDubs being extremely uncreative with their character design, the beast boss looks suspiciously like an orruk megaboss (albeit an extremely kit bashed version), right down to sharing the exact same pose and sporting the iconic skull on their right shoulder.
Because of their comparatively slightly lower tech-basis, they are usually armed with a Beastchoppa and a Beast Snagga Klaw. For a 'sidearm', he has a shoulder-mounted Shoota aimed and fired by a Targeting Squig.
On the tabletop, the Beastboss can be found on two varieties. The first is the regular old Beastboss on his good'ol legs. He is basically the Beast Snagga edition of the Warboss, meaning he'll only be useful if you focus your army on those newfangled greenskinz. He's not something to sneeze at, as while he only has a measly shoota that hits on a 4+, his melee weapons (a choppa with AP-2 and D2 and a power klaw-alike with S+4 AP-3 D2) are nothing to sneeze at, especially when focusing on what Beast Snaggas do best: Killing big things.
His second version is mounted on a Squigosaur. In this, you're essentially carrying a slightly tougher but considerably beefier monstrosity, carrying not only 9 wounds (just enough to not be visible behind cover) but also reducing all incoming damage by 1. Probably central to this entire shindig is the squigosaur's jaws, three extra attacks which can practically gobble up terminators - especially if you roll a 6 to hit and score 3 mortal wounds.