The Athlete feat (PHB, p. 165) gives the following benefits:
- Increase your Strength or Dexterity score by 1, to a maximum of 20.
- When you are prone, standing up uses only 5 feet of your movement.
- Climbing doesn't halve your speed.
- You can make a running long jump or a running high jump after moving only 5 feet on foot, rather than 10 feet.
Imagine the following scenario: a creature with a lot of movement speed, a maximum high jump equal or higher than 20 feet (possible, for instance, by being a Monk using Step of the Wind and wearing a belt of storm giant strength for a total of 24), the Athlete feat, and affected by the Cat's Grace option of the enhance ability spell.
The creature grapples an opponent (halving its movement speed unless the opponent's size is two categories smaller), and repeats the following, while maintaining the grapple, until it no longer has enough movement left:
- It gets a 5-foot running start,
- makes a high jump of 20 feet,
- lets itself fall down with the grappled creature, making both of them land prone and receive 2d6 bludgeoning damage (but the grappler creature does not take any thanks to Cat's Grace),
- and stands back up using 5 feet of movement (note — might not be required since you don't automatically land prone from falling if you don't take falling damage. I'm including it regardless to make it easier to imagine).
In summary, dealing 2d6 bludgeoning damage to the opponent for each 30 feet of movement spent. For example, a Medium creature with 300 feet of movement (possible, for instance, by being a Level 18 Wood Elf Monk affected by the longstrider spell, wearing activated boots of speed, and using Step of the Wind: [35+30+10]*2*2 = 300) and a maximum high jump of >= 20 feet that grapples another Medium creature right next to it and repeats the above steps could complete the process 5 times ((300/2)/30), for a total of 10d6 bludgeoning to the target.
Is there anything in the above scenario that does not work the way I think it does (such as a point in which the grapple would end early for some reason, or a point where more or less movement is actually required to be spent than what I think)?
The following questions, although not directly answering mine, are related:
Whether falling after a voluntary high jump makes you take falling damage (no currently accepted answer, although the most voted one seems to indicate that it's the jumper's choice whether he wants to take falling damage or not)
Whether grappling halves your maximum jump distance (not directly)
Whether the half-speed penalty stacks when grappling 2 creatures (seems likely, preventing the above scenario from being used efficiently with 2 targets, if it works at all)
Whether there is a per-turn limit of how far can a given creature fall, even if the individual falls are small (not by RAW, but yes by RAI, so that would limit an extremely fast character from doing more than 25 pile dives of 20ft each on a single turn)
Whether merely lifting the grappled creature above you to circumvent the need for a higher jump, Cat's Grace and the Athlete feat would work (likely not. You have to make more effort than that !)