This ferocious creature has plagued adventurers that enter it’s cave for hundreds of years. No one knows what it gaurds in it’s lair, but rumors of vast wealth continue to draw adventurers to it.
Barrow Dragons is a race of lesser dragons, nearly as small as wyverns or about the size of two oxen, that most often make their abode within dark and dry subterranean lairs.
Rather than making a baddy impossible to hit, consider giving it mega-hit points.
Super hard to hit leads to great player frustration. Allowing them to do damage leads to a sense of accomplishment. another variation of this would be to give the bad guy a forcefield that shows damage.You could also give them a mastermind ability that sluffs the damage of to minions who should be easy to kill.Once in a while a super high to hit encounter is ok ,but it should be few and far between.
Your mileage may vary