Subclass concept which could use recycled code of pox hounds to create a lovable mobile death shark.
There are two ways I can see it being implemented: passively active, where casting your ability activates extra utility. not sure what.
Method two is upon activation, the cyber mastiff uses one of mob spawn locations to run into the arena, this comes with the downside of limited time use but the upside they can more proactivly reach hostile targets quicker before they disapear back into the shadows.
As for how this useful.
Upsides: can be sent into gun lines to force them into mellee combat, can stagger and/or stun individual specials, can get to targets you may be too busy too, adorable and scary, might be pettable on the morningstar.
Downsides: likely not a massive DPS killer, could suffer being downed if they build it that way, if it’s pinning a special it can’t preform other actions unless called off, might not accept belly rubs in combat.
Upgrade potential: tuanting monsters, ammo/health delivery, can be sent to revive knocked down players, bleed attacks, second hound, glorafied loot vacuum.
As for what class main class it falls under I’d leave to fatshark, I feel this design could be translated to most if not all classes to some capacity.
 works for an arbites/enforcer themed build for sure.
I’m sure people have some interesting suggestions to how this could be further expanded.
Hell if fatshark use this down the line theres no garuntee it will even work like my idea, I’m just suggesting a support build.
providing the team want to go through the effort to modify some AI.