PLA should suffice, its going to be mostly under the ground. I recommend using a colour which is easy to see in the sand/mud so you can easily find it again.
You could do this without support, the pointy part will warp a bit but still be useful
Its about 0.5cm thick, 10.5 cm tall.
The opening is 0.2mm wide and 0.4mm deep.
The author marked this model as their own original creation.