Molotov Cocktail

The bottle does not fly far, so you are lobbing it down a corridor or over a ledge rather than sniping with it. What matters is the pool of flame that scatters on impact. Those flames sit there for several seconds and keep burning anything that walks through, so the trick is throwing where enemies are heading rather than where they are standing. Any liquid wipes the whole thing out on contact, which rules it out for anything fought over water.

Clearing a spider nest by hand is slow and gets you bitten from three directions. A couple of bottles into the mouth of one strips the webs out of the way in seconds while setting fire to whatever is hiding in them. The same idea works on the vine curtains in the jungle you would otherwise swing at one tile at a time.

Anything that brings a crowd takes the worst of it. Creepers around the Brain of Cthulhu bunch up tight enough that one throw catches several, and King Slime keeps feeding you fodder that wanders into the fire. The Eater of Worlds is the exception the game wrote in deliberately: fire does noticeably less to its segments, so bottles still help but they will not carry that fight.

The real device picked up its name in the Winter War of 1939. A Soviet minister insisted the bombs falling on Finland were food parcels, and Finnish soldiers started calling the gasoline bottles they threw back the drink to go with the meal.