Immovable Force

You know how to plant yourself firmly on the ground, bolstering your strength and steadying yourself like few others can.

As a bonus action, as long as you are not prone or incapacitated and are in contact with solid ground, you can go into Immovable Mode. You gain the following benefits:

• You have advantage on Strength (Athletics) Checks and Strength Saving Throws.
• If you are grappled, before the grappler can move you, it must make a Strength (Athletics) check contested by your Strength (Athletics) check. If it loses, it can't move you until the beginning of it's next turn.
• As an action, you can shove a creature a considerable distance away from you. The target must make a Strength (Athletics) or Dexterity (Acrobatics) check contested by your Strength (Athletics) check. On a loss, a creature at least one size smaller than you is pushed a number of feet away from you equal to ten times your Strength Modifier, halved if it is the same size as you and halved again if it is one size larger, always rounding it up. 10ft. is the minimum distance it can be pushed regardless of size.

Immovable Mode can be ended as a free action. It ends earlier if you move or are moved more than 10 ft. at once, are knocked prone, incapacitated or somehow lose contact with solid ground. This feat can be safely used once every short or long rest. Each repeated use not punctuated by a rest will accrue one level of exhaustion.