Seeing that he finally had reinforcements, he quickly cast the wall of stone spell, and encircled himself in as thick of rock as he could, making sure it was just a bit bigger than he absolutely needed. Safely ensconced in the rock, he HOPED the creature would try to batter through it to get to him. If it did, he planned to teleport behind it, and then just bombard it with battering forces while hopefully getting it stuck in the too small rock 'cave.'