Brynjolf's Unforgettable Board

This spell creates a surfboard shaped plane of force, up to 8ft long and up to 3ft wide, that behaves exactly like a surfboard. It floats on liquids and appears in an unoccupied space of your choice that you can see within range. The board remains for the duration, and can hold up to 500 pounds. If more weight is placed on it, the spell ends, and everything on the board falls to the ground.

The board is mobile and ridable while you are within 20 feet of it. If you move more than 20 feet away from it, the board follows you so that it remains within 20 feet of you (like an ankle tether) 

If you move more than 100 feet from the board (typically because it can't move around an obstacle to follow you), the spell ends.

Designed by a wandering scholar who wished to be able to surf at anytime.