I ran my players through this with a completely normal Spawn, no modifications to make it more "pathfindery", and it mauled them. The fear aura scared off the rogue and the druid's raptor animal companion, leaving a low AC barbarian, low AC oracle, and low AC wizard/druid. THe barbarian got three worms, the oracle got one, and since everyone was fifth level, the oracle didn't have remove disease. The druid had the heal skill, so he saved the day, but not before the barbarian took 7 points of int damage to his already low int score. They had their backsides saved by a random encounter with a priest of St. Cuthbert while they were rushing back to town to get the Int drain cured. Loads of fun. The main danger of a spawn, as far as I can tell, has always been the disease they carry and the worms, easily making them a major danger with only one or two bad rolls. CL 5 is very appropriate.
