If you see a tree like this, that's covered in spikes and has these weird pumpkin shaped growth on it- be careful! That's a sandbox tree, and its seedpods literally explode. Each slice of that pod contains a seed, and as the case dries, the fibers shrink and start to pull on each other making the whole thing want to open up like a flower, but it can't. Eventually, the tension becomes too much and the whole thing cracks open, flinging the large flat seeds. As they spin away, they accelerate at an average rate of 41,000 meters per second per second to reach speeds of up to 70 meters per second. So you definitely do not want to be in the way! The tree however, also doesn't want you to be in the way, because the point is distance. Its not trying to hurt you. The seeds are big because they're packed with fuel, so they can be competitive in a dense forest.  But that also means they could end up competing with each other and with their parent, and thus an explosion evolved to flinging the seeds more than 40 meters away, which is like half the length of a football field.