What it did: "ignited fuel tanks and burst the tires"
What it did it to: "abandoned vehicles"
I do find "incandescent" hard to imagine. Because it's just fat, and it'll carbonize before becoming incandescent. Maybe "flaming margarine" or something. Also, "listened" indicated that they heard, but didn't see.
It doesn't really need punctuation. But maybe this would be clearer:
They listened as a river of incandescent margarine ignited the fuel tanks, and burst the tires, of abandoned vehicles.
Or maybe:
They listened as a river of incandescent margarine engulfed abandoned vehicles, igniting fuel tanks and bursting tires.
Belated edit: Maybe "river of incandescent margarine vapor". But it wouldn't really be margarine anymore. Without enough oxygen to fully burn, it'd be mostly a mixture of carbon particles, H2O, H2, CO and CO2. Like a candle flame.
The agent: "river of incandescent margarine".
What it did: "ignited fuel tanks and burst the tires"
What it did it to: "abandoned vehicles"
I do find "incandescent" hard to imagine. Because it's just fat, and it'll carbonize before becoming incandescent. Maybe "flaming margarine" or something. Also, "listened" indicated that they heard, but didn't see.
It doesn't really need punctuation. But maybe this would be clearer:
They listened as a river of incandescent margarine ignited the fuel tanks, and burst the tires, of abandoned vehicles.
Or maybe:
They listened as a river of incandescent margarine engulfed abandoned vehicles, igniting fuel tanks and bursting tires.