Phyrexian Marauder

Artifact Creature - Construct

Phyrexian Marauder enters the battlefield with X +1/+1 counters on it.

Phyrexian Marauder can't block.

Phyrexian Marauder can't attack unless you pay for each +1/+1 counter on it.

Phyrexian Walker

Artifact Creature - Construct

"I have heard terrible tales of black rains, ashen fields, and metal that screams. I have consoled myself that the tales were a myth of some fevered mind. But today I saw a walker-and now I fear the truth."
-Kasib Ibn Naji, Letters

Shifting Wall

Artifact Creature - Wall

Defender (This creature can't attack.)

Shifting Wall enters the battlefield with X +1/+1 counters on it.

"You'd almost think Volrath doesn't want me here."
-Gerrard

Shield Sphere

Artifact Creature - Wall

Defender

Whenever Shield Sphere blocks, put a -0/-1 counter on it.

"My Soldiers know that they need never fear for their protection."
-King Darien of Kjeldor

Endless One

Creature - Eldrazi

Endless One enters the battlefield with X +1/+1 counters on it.

It embodies all possible meanings of the word "infinite."