If you live in a desert, this thingy (an olla lid) will make sense.

For everyone else: desert gardens need water for their plants to survive through the hot summers. Historically, one method of irrigation was to bury a terracotta jar in the ground, which then slowly released water to nearby plants. This works because terracotta wicks water. (Please note that a clay pot won't work - it has to be genuine, unglazed terracotta.) These special jar shapes are called "ollas" and they have a long narrow neck so that the reservoir can be filled from above-ground. The problem will ollas is that they are expensive to make and buy. Therefore, this 3D printed lid allows one to buy a normal and cheap terracotta pot, plug the pot's drain hole, and then turn it into an instant olla with this 3D printed lid.

The lid covers a buried 6" pot, while the the 2.5" wide funnel fits a standard garden hose sprayer. The lid is 165mm in diameter, 2.5mm thick, and has air holes in the lid so that the water can be quickly sprayed into the pot without resistance. The funnel is intentionally placed off-center so that the water pressure from the hose isn't directly hitting the pot's plug.

There are two optional accessories to go along with this olla lid.

1. A dipstick to check the water level in your pot: https://www.thingiverse.com/thing:6640962
2. A frog lid to cover the funnel opening and prevent evaporation: https://www.thingiverse.com/thing:6641026

This is my first attempt at designing anything for 3D printing, so I would really appreciate comments about what to change for next time