What could be the green spiky thing that got stuck in your foot?

Based on the description you provided "a green spiky thing," there are several possibilities for what it could be:

- Sea urchin spine: If you were walking in a coastal area or had contact with the ocean, it's possible that you stepped on a sea urchin and one of its spines became embedded in your foot. Sea urchins have long, sharp spines that can easily pierce through skin.

- Cactus needle: If you were walking in an area with cacti or were handling a cactus, it's possible that a cactus needle got stuck in your foot. Cactus needles are also very sharp and can easily penetrate the skin.

- Thorn: There are many types of plants with thorns, such as roses, blackberries, and thistles. If you were walking through an area with these plants, it's possible that you accidentally stepped on a thorn.

- Glass Shard: If you stepped on a broken glass bottle or some other sharp piece of glass, it's possible that a shard became lodged in your foot.

It's important to seek medical attention if you are unsure what the object is or if it is causing significant pain or discomfort. Removing a foreign object from the foot can be difficult and may require medical assistance.