Like OP said, it's a Quiver Tree. The genus is Aloidendron which literally means "Aloe branched." And that's what they are. They are very closely related to the aloes you can buy in the grocery store, but they grow in a tree form. They have huge inflorescences of yellow flowers that are just like the aloe vera flowers.

As an aside, they are called Quiver Tree because the people native to the area would take a branch, hollow it out, and use it to store their arrows in.