"This low-level gel monster is engulfed in flames. Its strength varies depending on its size. It tends to explode if attacked from close range, so the use of spears, arrows, and other ranged weapons is advised."
Breath of the Wild
These Chuchus appear abundantly in the Eldin region, especially on Death Mountain and throughout the Eldin Mountain Range. As they are covered in flames, defeating one will cause it to explode, and potentially burn Link or other nearby non-fired based enemies. Fire Chuchu come in three sizes, with each having its own health meter. The smallest chuchu has a health of just 3 HP, the medium-sized one has a health of 20 HP, while the largest Fire Chuchu has a health of 48 HP.
When a Fire Chuchu attacks, it will launch itself towards Link, setting off a burst of fire right around itself. This attack can set Link on fire, unless Link is wearing armor that is fireproof, such as the Flamebreaker Set. Alternatively, Link can avoid being burned if he has drunk an Elixir that has Flame Guard, such as the Fireproof Elixir.
After a Fire Chuchu attacks, there is a short cool down period, where Link can safely defeat the enemy. If Link defeats the enemy while it is still engulfed in flames, it will explode when defeated. Thus, it is best to attack a Fire Chuchu from a distance, using arrows or spears. These enemies are vulnerable to ice-based attacks and a single attack with an ice weapon or ice arrow will defeat a Fire Chuchu instantly. When defeated, Fire Chuchu will exclusively drop Red Chuchu Jelly as a reward.
Age of Calamity
Hyrule Compendium entry of the Fire Chuchu.