Pachypodium lamerei is a succulent flowering plant from Madagascar and as such is often referred to as the Madagascar Palm even though it is not a palm at all.
It is unusual as succulents go as this is classified as a stem succulent which means it does most of it's photosynthesising through its trunk.
The greeny/grey trunk has large thorns that can be up to 6cms long and produces long, thin leaves mainly from the top of the plant.
It also produces large and very fragrant white flowers, that look very much like those of the Frangipani, and overall it makes a very striking plant with much to admire - though you would always take care around its thorns. Note that they rarely flower when kept indoors.
This is one of the best known pachypodiums and is relatively easy to grow and propagate in warmer climates and can also be grown indoors where it must have as much light as possible.
There is a dwarf variety called Ramosum which goes well in large pots or tubs.