Borderlands – Where to farm after killing the final boss

I don't really see much options on slowing enemies down, so I'll add tips on surviving close quarters combat, and/or escaping it when playing as a Sniper (assuming you're focusing on the 'Sniping' skill tree).

• See the 'Status Effects - Stunning' article at the Borderlands wiki (most of it is written for Borderlands 1, but a lot still applies to Borderlands 2). It dicusses how enemies are stunned, which should slow them down.

• Try focusing on increasing the At 0ne with the Gun skill in the Sniping skill tree:

  It greatly improves accuracy of sniper rifles when aiming from the hip. It also increases the reload speed and magazine size of sniper rifles.

  This well help you to better shoot your sniper rifle without using the scope - useful as a lot of the skills in the 'Sniping' skill tree improve the efficiency of sniper rifles specifically. This will make it easier to fight or whittle down enemies while escaping close quarters combat.

• Hyperion 'Singularity' grenades pulls in nearby enemies before exploding, potentially slowing them down, while dealing heavy damage. When overwhelmed, throw a grenade, while going for the nearest cover.

• Torgue/Maliwan 'Nova' shields will fire elemental blasts once depleted. They could help damage or whittle down nearby enemies in close-quarters combat, making it easier to fight or escape.

• Use a Relic that increases Decepti0n's cool down rate ('Proficiency' relics) or helps improve 'Fight For Your Life' time ('Tenacity' relics or Sheriff's/Deputy's badge). You will either be more likely to escape with Decepti0n when you need to use it, or have more time to get a second wind, when crippled.

• Get a 'Professional' class mod. It increases reload speed and shield capacity, making you take more damage, and making it easier to fight back without using the sniper scope or a sniper rifle. It will still help if you're firing the sniper rifle unscoped and you have At 0ne with the Gun skill points. Another option is to equip a 'Spy' class mod (faster Decepti0n cooldown rate) or a 'Survivor' class mod (increase max health and health regeneration).

• When playing co-op, let you non-sniper allies be at the front lines, and just snipe enemies from a safe distance.

• Be wary of places where enemies might spawn. Also, have a strong backup non-sniper gun ready, or use your Sniper rifle unscoped if you have At 0ne with the Gun skill points, when fighting or escaping close quarters combat.

Based on this forum post and personal experience, Vermivorous cannot spawn on normal mode. According to the description in the video below, he'll spawn at level 42 in playthrough 2 and 53 in 2.5.

Thanks to Orc JMR for additional information