Shieldcaster

When Shieldcaster enters the battlefield, forge a
Shield. (Create a colorless Shield artifact Equipment
token with "Equipped creature gets +0/+1" and
"Equip {1}".)
Stalk {u} (At the end of each block step, if there is an unblocked creature attacking you, you may
cast this card for its stalk cost. If you do, choose an unblocked creature attacking you. This creature blocks
that creature.)