Morpheus' arms enable you to put your horse to bed and age him as many times as you want, without consuming aging points. This object can only be used on horses over the age of 3.

NB: the effect of Morpheus' arms stops at the age of 30 for immortal horses. Once they reach this age, the horses can no longer be aged indefinitely. Of course, horses with Morpheus' arms no longer find aging points.