Borderlands 2 Cult Following: False Idols can be unlocked by completing the Cult Following: Eternal Flame mission we receive from Lilith.
Finishing the latter, gives us access to the next one, which becomes available immediately after speaking with Incinerator Clayton.
The Borderlands 2 Cult Following: False Idols quest requires our presence in the Frostburn Canyon region where we must find and defeat an enemy named Scorch.
Incinerator Clayton has asked you to kill Scorch, a demigod (his words) who is stealing (also his words) followers from the Firehawk, despite that Lilith does not give a spiderants patootie about who worships her (not his words).
Item: Assault Rifle / Shield
Experience: 1450 XP
For the Borderlands 2 Cult Following: False Idols mission we have to travel further into Frostburn Canyon, following the waypoint on our map.
If we take the shorter path (to the west) we might encounter a powerful goon who carries a loot chest on his back. If we meet him we must be aware because he is incredibly strong and he can regenerate his life, but also worthy of killing, because we can find better gear in his chest.
When we arrive at our destination, a powerful spiderant named Scorch will appear. Obviously, he can’t be hurt by fire weapons, so we need to use something else (a different elemental weapon), and try to finish him as fast as we can, because he is helped by some fire spiderants, as dangerous as he is.
Additionally, moving around helps us a lot, because Scorch has a fire shield around him, inflicting AoE damage.
The shield detonates if we get near Scorch. Staying at a safe distance on the other hand, means that well have to avoid his fire projectiles.
After killing him and receiving a message from Lilith, we can go back to Incinerator Clayton to collect our reward for Borderlands 2 Cult Following: False Idols mission (we have to choose between a shield and an assault rifle).
Speaking with Clayton will also unlock the next mission in the series, named Cult Following: Lighting the Match.