Helldivers 2

Good stratagems against it, don't expect everyone can follow if you don't have a pre-made party. (as there are host/players just want to complete the mission and ignore this bullet sponge.) For killing it:(150k health)

• Orbital Laser : high DPS, with burning damage.(don't know the multiplier yet, waiting for data miner. but big enemy usually have higher fire tick damage. )
• Orbital Gatling Barrage: AP5 so throw at the ground where it emerge belly side), high enough DPS, you should be able to land almost all shots(9s duration) because the size of it.
• ATE(anti-tank emplacement): if someone can escort you it offer very good AT rounds(30) and damage.
• Patriot Exosuit: 14 AP6 rocket @ 1250 damage. If you have a friend one bring Emancipator Exosuit that can shoot a lot of shots(200) @ 300 damage when any of the armor is blown off. Exosuits are really good dealing with tunnel situation, but do not walk on the bridges, as exosuits will collapse them.
• Commandos: slightly higher damage 4 shots than EAT, shoot and forget.
• Portable Hellbomb: long cool down and some mission objective does require it. you usually can't get close enough to get the max damage if you are not close enough when it emerge, as it has certain range around it's root that cause tremor and hard to walk closer. (bomb max damage range is 25m after 25m the damage fall off pretty fast. )
• Recoilless Rifle: if running with a friend with assisted reload + resupply backpack, you just need 47 shots. a full RR + resupply back pack gives you 7 + 3*4 = 19 shots. supply hellpod pack can refill "full" ammo if you have the upgrade(Superior Packing Methodology) so make sure only the guy have that upgrade calls supply pod. thus a supply pod has 6*4 = 24 shot. if you have the resupply back pack ready to drop before you engage, you can kill the hivelord in about 3~4 times it emerge from ground. 19 shots + 24 shots + another 12 shots from new resupply backpack fills. (resupply backpack do not benefit from that ship upgrade.)

Break the belly or back (with big guns) and then pummel the hole with AP3+