Down by the dock here there are a bunch of these spikey pods hanging from the trees just on the landward side of the mangroves.
We were curious what they are, so we did some some digging and found out that they’re called a nickerbean. When they dry out, they open up like this:
And out come these two gorgeous greyish-green seeds.
Before the seeds come out they make a nice rattling noise, but you have to be careful shaking the pods because of all of those sharp spikes.
Apparently these are native and are the native habitat of several species of butterfly. You can find more info here.