The spawn chance of chubby enemies is very low, whenever a badass enemy is spawned, it has a rare chance of spawning as a chubby. This makes them very difficult to find in the wild, especially at lower levels and play modes.
Due to their spawn nature, chubbies are more frequently encountered in areas that have a higher chance of spawning badasses and among enemies that are more frequently found as badasses, most notably varkids. Other factors such as the playthrough mode and the number of players in the game also work to increase the rate of badasses spawning, thus increasing the rate of chubbies spawning. A 4 player game will be much more likely to see a chubby enemy than a single player game.
Places that more easily spawn chubbies:
- Caustic Caverns
Due to the nature of varkid evolution, it is easier to spawn chubby enemies here than in other places. Also of note are the spiderant colonies. These make the Caustic Caverns one of the best places to farm chubbies without DLCs. The areas where enemies spawn are also quite conveniently isolated and segregated, which allows for farming without other enemies attacking their spawns. Chubby farming here couples well with farming for Vermivorous the Invincible.
- Tundra Express
This is another area where chubby farming is made easier due to the presence of varkid colonies. Although this area has other enemies that will target Vault Hunters and interfere with farming, chubby farming here couples well with farming for Vermivorous the Invincible.
- The Dust
The Bug Gulch area behind Ellie's Garage has a large number of spiderants with little resistance from other enemy types. Farming this area is best coupled with farming The Black Queen, Gettle, and Mobley.
- Natural Selection Annex (DLC only)
During the Creature Slaughter missions, badasses have a much higher rate of spawning, though in order to farm this area effectively, one of the higher rounds has to be deliberately failed, preferably on the final wave after the possibility of additional chubbies has been exhausted.
- Arid Nexus - Badlands
There are ~12 skag dens on the map. The quest Hungry Like the Skag will highlight the spawn areas on the map. All dens are able to spawn Chubbies and Badasses. Nearby to the Fast Travel station, there are 6 that can be checked quickly, 3 more on the ridge to the right of the character spawn, 2 near a house area just ahead over a small ledge, and 1 by the skag pool straight ahead of the Fast Travel station. Utilizing the Save/Quit strategy, this area yields fast and reliable results in single player.
- Three Horns - Valley
If using the Fast Travel station, there are a few skags on the way to fight Doc Mercy. Utilizing the Save/Quit strategy can be used to quickly check for tubby skags.
- Hallowed Hollow (TK Baha's Bloody Harvest only)
The colony and the last infested forge spawn Spiderants workers and above more commonly than spiderlings, badasses have a higher chance of spawning resulting in more chubby Spiderants than in other locations. Using the Save/Quit strategy will yield reliable results.
- Killing a chubby enemy unlocks the "Cute Loot" achievement.
- In Ultimate Vault Hunter Mode, Chubby are renamed as Tubby enemies.
- All Chubby enemies have a chance to drop any of the pearlescent or legendary items (except the Norfleet, the Ogre, the "magic" grenades from Tiny Tina's Assault on Dragon Keep and Slayer of Terramorphous class mods) and have an increased chance to drop legendary class mods, the Bunny, or Whiskey Tango Foxtrot.
- The spawn chance for a Chubby/Tubby is 0.5% for every potential spawn location.
- Tubby Skeletons have a special drop pool for the Infinity, and will drop it regularly, though not as often as Legendary Class Mods.