Snake (SSBU)/Back aerial
Snake does a kick backwards in the air while in a plank position. Commonly known as the Sleeping Bag by the Snake community, it has fast startup at frame 7 and possesses large, disjointed hitboxes that give the move very good range. The clean hit deals high damage and excellent knockback, easily being able to KO at high percentages, especially if it connects with the sweetspot located on Snake's feet. The late hit deals far less knockback but still sends the opponent decently far away. Its speed and power make it a useful approach option if used in a reverse aerial rush, as well as a useful edgeguarding option.
The attack also has a very large amount of active frames, making it a potential landing option, as the late hit can act as a "get off me" option as Snake is attempting to land.
It does have some flaws, however. The most noteworthy is its high landing lag, and while it autocancels in a full hop, it does not in a short hop. As a result, it is unsafe on shield and easy to punish if it whiffs, much like Snake's other aerials.
Overall, back aerial is a a highly rewarding move due to its speed, power, range and long lasting duration, making it useful both offensively and defensively. However, it must not be used carelessly as to not leave Snake vulnerable to punishment.