His card starts out as a simple looter, but get 14 cards into your graveyard (get it?) and he flips into Hades, a mighty avatar that lets you play cards from the bin
xD Shu Yun is still a great option and playable too but to be honest with you, i just love the Chain-Reaction Narset pulls out after you attacked with her
Its a lot easier to get working to kill a player than other similar effects
You can also set up defenses with Sphere of Safety to make it harder for your opponents to attack into you while you get your summon chains going
Once it lands, Tyrranax Rex has ward 4 and haste, meaning it is attacking as soon as it comes down, and even if your opponent wants to stop it, your opponents are going to be taxed to oblivion to resolve the spell
With trample, infect, and indestructible, Blightsteel Colossus is either always pushing poison counters through or is taking out multiple creatures a turn to stop it