How much health does tagilla have?
Whether you are playing for the Halloween Event or just want to kill this boss, knowing how much health does tagilla have is important. His health pool is crazy and his defensive capabilities are insane so make sure to bring a high-caliber weapon with a good ammo type that can punish him and deal enough damage to kill him.
Aim for his head and not his thorax as his welding mask does not protect it well-enough. The other limbs, like his stomach, are not covered by the armor so aim for those if you have low pen ammo or high flesh damage ammo.
The best shotgun ammo to use on Tagilla is the 12/70 HP Slug "SuperFormance", or 12/70 HP Slug Copper Sabot Premier. It's a good choice on Factory, Dorms area in Customs, Interchange, Labs, Shoreline's resort, and other close-ranged hot areas.
Alternatively, you can go with the 5.45x39 mm 7N39 "Igolnik" since it has a lower chance of dropping. If you want to be more thrifty, you can also use the 12/70 AP-20 Slug which is a modded AKS-74UN.
How to kill tagilla on the factory map
If you are looking for a way to kill Tagilla on the factory map, one of the most effective ways is to run in from the top level and run along the catwalk overlooking half of the Factory. This will allow you to sneak up on him and shoot him from afar without being seen by others.