King K. Rool (SSBU)/Up throw
King K. Rool's up throw is an attack reminiscent of an Argentine backbreaker. One of the most damaging throws in the game - dealing 16% at base and 20.1% in 1v1 fresh - this move is frequently used for building damage. With just a few up throws and pummels, the opponent can very quickly find themselves at a KO percentage. This is the heart of K. Rool's damage building.
Up throw is often used once forward throw to dash attack has been exhausted (which is one use), as there are no more throw combos past that percentage until down throw starts working. At 0%, the hit advantage is just -1 with tumble active, meaning K. Rool can take the opportunity to get reads and mindgames in. This is usually done with up tilt to cover jumps, or other grounded options to cover airdodge lag, usually a pivot grab. These interactions can lead to extremely high damage output and large amounts of pressure. Up aerial can also be used for a very early stock while covering jump and slow airdodges.
Up throw also has respectable KO potential with platform assistance at higher percentages. While niche by stage limits, the top platforms of Yoshi's Story and Battlefield allow a fresh up throw to be a threat. Using pummels to unstale up throw prior is important to achieve this. Outside of this though, up throw does not KO until very high percentages (~180%), long after a down throw into a true followup begins working. As such, while powerful when it works, up throw is not a conventional kill throw.
Up throw on a high platform can be used to set up for Propellerpack for a sneaky KO, but this often requires a jump read to be of use, as well as a jump or two from K. Rool himself so he can reach the blast zone. Given that Propellerpack deals no hitlag, it requires solid DI from the opponent to escape once caught. Good swerving of Propellerpack is also necessary for it to work. If it does work however, it's essentially a free stock. This is most effective on stages with no ceilings or those with high platforms, such as the aforementioned Yoshi's Story.
Up throw does have its flaws, though. Its KO potential is limited to niche situations - and sometimes by stage - which makes it strictly for damage. It also has no combo potential due to the limited hit advantage at 0% and iffy launch distance thereafter. While these flaws are minor due to the potential for mixups and the sheer damage, they should be considered during use.