Activate this ability only once each turn
Myriad is just a plain powerful ability, and being able to catch up in multiple ways by hitting different players is pretty effective and aggressive
(Did you know that Spectacular ShowdownSpectacular Showdown is the only card that can give every creature on the battlefield double strike?) It's no secret that I love aggro
This can be done through Sneak Attack and Phyrexian Altar, and a combo deck might conceivably play both
While the Worldsire doesn't have trample or any other form of evasion, it should be large enough that you can kill anything that crosses its path, and the land ability should be what you're using this for, with things like Valakut, the Molten Pinnacle or Field of the Dead
The card also shows Colossus, Bishop, Jean Grey, and Ice Man, in case you were missing some of our other X-Men