The Goliath of Velumburg

Affinity for Artifacts, X is equal to 15.
Trample, Annihilator 3, Indestructible.
At the beginning of your upkeep sacrifice The Goliath of Velumburg unless you sacrifice an Artifact.
The Goliath of Velumburg, the ultimate war-machine, created by the one and only George Maycock. Powered by four cold fusion reactors, not something you would want to be against on the battlefield