Christ Thorn Plant (Euphorbia milii)
Euphorbia milii is a species of flowering plant, native to Madagascar. It's also called Christ Thorn, Christ plant and crown of thorns. The species is from the spurge family Euphorbiaceae. Usually the flowers are deep red, but this cultivar flowers are colored yellow.
Quite an interesting plant which allows quite a lot neglect. In fact, it usually gets hurt by overwatering, not underwatering. It rather stays dry than waterlogged.