The big Mountain Golem

The big Mountain Golem enters to the battleffield as an artifact.
Meanwhile The big Mountain Golem is an artifact,
it can only block. Whenever The big Mountain Golem blocks, another blocking creature under your
control gains -1/+3 until the end of turn. Activate this hability only if The big Mountain Golem is an artifact. Sacrify one or more permanents: The big Mountain Golem is an X/X .
It enters to the battleffield with the same number of +1/+1 counters as the number of sacrified permanents less