because of the sharp spikes on your cactus body, those who try to hit you with unarmed attacks will take 2d4 piercing damage.

Because of your small size, you are more difficult to hit with attacks, making your AC an 18.

You ARE nature, giving you a advantage in the Nature skill.

Because you are a cactus you are an expert in all things spikes.

starting at 3rd level you can grab your cactus body with your mechanical arms and throw yourself at a target within 300 ft of yourself. using the YEET action leaves your AC at 1 until your Cactus body is retrieved

You can cast spike growth at will

Your carrying capacity is that of a Gargantuan creature