From Brotato Wiki
) burning damage
Item
Incendiary Turret is an in-game item that can be bought from a Shop or can be found in a Crate. Most Items modify the Stats of the player, and some of them provide additional effects.
Buying the item spawns an Incendiary Turret at the beginning of each wave that attacks enemies within 300 range for 1 damage, piercing enemies and inflicts burn to targets dealing 5 + (33% ) damage every second for 8 seconds. Attacks every 0.28s.
It is identical to the turret spawned by a Wrench Tier 2.
Scaling
Turrets being Structures are unaffected by Primary Stats, such as Damage, Life Steal, Attack Speed, Crit Chance. But are affected by Engineering.
Turrets are affected by Secondary Stats such as piercing and bouncing granted by the items 
Bandana & 
Ricochet. The Incendiary Turret get +1 Burn damage from 
Scared Sausage, and 
Snake helps inflict burn to more targets.