Blightsteel Colossus

{12}Artifact Creature — Phyrexian Golem11/11

Trample, infect, indestructible

If Blightsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.

Indestructible. This can't be destroyed by damage or by effects that say "destroy." · CR 702.12

Trample. Excess combat damage beyond what's lethal to blockers can be assigned to the player or planeswalker it's attacking. · CR 702.19

Infect. This deals damage to creatures as -1/-1 counters and to players as poison counters. (10 poison = that player loses.) · CR 702.90

Damage from a source with infect is damage in all respects. If the source with infect also has lifelink, damage dealt by that source also causes its controller to gain that much life. Damage from a source with infect can be prevented or redirected. Abilities that trigger on damage being dealt will trigger if a source with infect deals damage, if appropriate. (2020-08-07)
Damage that a creature with infect deals doesn't result in damage being marked on a creature or a player losing life. Instead, it results in that many -1/-1 counters being put on that creature or that many poison counters being given to that player. Damage dealt to planeswalkers still results in that planeswalker losing that many loyalty counters. (2020-08-07)
The -1/-1 counters remain on the creature indefinitely. They're not removed if the creature regenerates or the turn ends. (2020-08-07)
A player who has ten or more poison counters loses the game. This is a state-based action. (2020-08-07)