I think they were fudging the rules a little with the belt giving Mr. Scruffy THAT much strength. Even a +6 to a cat wouldn't let him Bull Rush a wolf through a rock wall...
I'm pretty sure Mr. Scruffy didn't bull rush Sir Scraggly through a rock wall, he bull rushed him through the hole in the wall that Thog made earlier.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.