This is the latest card from Wizards called Brightsteel Colossus:
Blightsteel Colossus 12
Artifact Creature - Golem (Mythic Rare)
Trample, infect
Blightsteel Colossus is indestructible.
If Blightsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.
11/11
Compare to Darksteel Colossus (Which we've already established as broken):
Darksteel Colossus 11
Artifact Creature — Golem (Mythic Rare)
Trample
Darksteel Colossus is indestructible.
If Darksteel Colossus would be put into a graveyard from anywhere, reveal Darksteel Colossus and shuffle it into its owner's library instead.
11 / 11
So for just 1 mana more you get infect on the blightsteel colossus and since it has trample it can put on you 11 poison counters on one game making you lose game in 1 turn
and its indestructible
and if opponent somehow does manage get to get rid of it, it will come back to your library.
maybe too broken?