What happens if you reverse polarity when jump starting a car?

What happens if you reverse polarity when jump starting a car, if you reverse polarity when jump starting car meaning you connect positive jumper cable to negative terminal and negative to positive, you create dead short with reversed polarity causing very large current flow, sparks, overheating, and serious damage to both vehicles electrical systems. What happens includes immediate large sparks when cables touch, battery can overheat, boil, and potentially explode due to excessive current and hydrogen gas, cables can melt and cause burns, fuses can blow, fusible links can melt, alternator diodes can be destroyed, ECU computer can be damaged, and wiring can be burned. Reverse polarity jump start can damage sensitive electronics in both cars, costing expensive repairs, and cause fire hazard. Modern cars have many electronics that are sensitive to reverse polarity, so damage can include instrument cluster, radio, and engine control module. So what happens if you reverse polarity when jump starting, you get sparks, potential battery explosion, melted cables, blown fuses, damaged alternator and ECU, and fire risk, with correct procedure being red positive cable to positive terminal of dead battery then positive of good battery, black negative to negative of good battery and to unpainted metal ground on dead car, not to negative of dead battery, to avoid sparks near battery, with polarity must be correct to prevent damage.