From Brotato Wiki
Scared Sausage is an in-game item that can be bought from Shop or can be found in a Crate. Most Items increase the Stats of the player while some of them provide unique effects.
Scared Sausage gives any hit produced by you a 25% chance to inflict burn for 1 + (100%) each second, for 3 seconds. Each additional Scared Sausage increases the chance to inflict burn by another 25%, up to a max of 100% when you have 4.
The Scared Sausage also gives +1 to the base burning damage of weapons that already inflict burning on hit such as the Flamethrower. Since Scared Sausage costs more than 1 elemental damage in general, you might not want to buy Scared Sausages unless you actually use its ability to inflict burn. Any Sausage beyond the first also increases the damage dealt by the burn it inflicts itself by +1.
There are a few exceptions that cannot inflict burn with Scared Sausage.
- Spawned projectiles from Alien Eyes, Baby with a Beard, Lightning Shiv, Cacti Club and other weapons cannot inflict burn. The main attack with the weapon can still do it as normal.
- Damage from Baby Elephant or Cyberball doesn't spread either.
- The Explosion from Bull or Landmines can't spread fire, but explosions from Rocket Launcher and other weapons can.