This egg was given out for Creature Release Week in January of 2015.
Manticore eggs are notoriously hard to come by. The only place they can be found is deep in Ark's jungles. The nests are also guarded by the Manticore parents, who react violently to anyone trying to steal their eggs. However it is possible to have the parents gift you an egg. This requires winning some sort of contest against one of the parents. It is best to propose the contest yourself otherwise you my find yourself in a contest that only a Manticore can win.
In many of Ark's legends and ancient tales Manticores are an adversary to the ancient heroes and are portrayed in a negative light. The negative light cast upon Manticores continues to present day. However, Manticores are actually very misunderstood creatures. Manticore society is based around challenges and relatively friendly brawls. So it is little wonder that the species was deemed violent when the first people to meet Manticores were challenged to a fight, unknowing that it was meant to be friendly gesture.