Last night my character got surprised by a constrictor snake while on watch and was quickly grappled and started taking constriction damage. The other characters woke up and started attacking the snake. We thought that there was a rule that if you were sharing a space with someone else, your allies had a 25% chance of hitting you. It's not in the grappling section of the 3.0 rules, but I know it's in the bull rush rules. Is this a rule, or were we dreaming? It seems to make sense.