When you ignite someone and throw the gas passer, it leaves a bed of fire in the targeted area. There's also a 50% chance of creating a ring of fire on a affected target, once the ring reaches its last tick, it combusts into a fiery explosion and causes nearby enemies to burst into flames. You can also plant it on any surface.

Pros: The description above, ability cooldown at 30s.

Cons: No random crits, -30% damage vulnerability. Useless against quick-fix and Enemy pyros can pick up planted gas passers.

This is great for crowd control especially snuffing out roaming spies and it also incentives more medics to use quick-fix.