As of the Terraria Journey's End update, some fiery critters - namely the Lavafly, Hell Butterfly, and Magma Snail - can spawn in the Underworld. When used as fishing bait, these critters allow one to fish in lava, a very lucrative activity.
Needless to say, gathering these critters is more dangerous than finding regular bait like worms or fireflies, and they also seem to be fairly rare. How can I increase my chances of finding lava bait?
The spawn rates of critters are affected by things like Water Candles and Battle potions, so by using either of these you can speed up the gathering of them.
This does have the unfortunate side effect of also increasing enemy spawn rates, so if you’re worried about danger this may not be ideal for you.
I would recommend using potions such as water walking or obsidian skin to make your life a bit easier in the Underworld. But, there is no real easy way to stockpile these critters.
Ive theorized that creating an AFK farm with several housed npc's within range of the AFK farm, then using a battle pot and water candle could force only large quantities of underworld critters to spawn, but Ive never tested it and cannot confirm or deny its value/effectiveness. Instead I've always opted for a Hotline Fishing Rod and Lavaproof Hook/Tackle Bag combo. a bit grindier, but easier than trying to set up an AFKeque farm in the Underworld.
If you get the lava proof fishing hook accessory then you don’t need the lava critters. It can be found in obsidian crates and hellstone crates. I don’t know how to increase the rate that you get them.
