“ 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”
“ Your Pillow> This magic pillow is "+2" comfort and remains cool despite the temperature. It also shrinks to the size of a cigarette box for easy transportation. These are WILDLY popular wth those who have to travel(especially adventurers) . They command a huge price far outside it's true value , sometimes selling for thousands of gold pieces in a world where stating fighters are often equiped w +2 Swords. The method of creation is lost but sevral enterprising mages are trying to recreate this, with no success.”
“ The forests, the swamps, the lands lost to wilderness, fang, and willow. These lands are home to the creatures of wiing, tooth and claw. Some far more capable of fending off the hominids, others still, are less fortunate, falling prey to spears, arrows, and dogs. As the hominids encroach upon the sacred woodlands and miry bogs there are times that the thorns and vines are animated by the spirit of the land in order to fight. In this way the mysterious guardians are formed. In the shapes of wolves, bears, and many other greater and more terrible beasts, each with eyes of glowing emerald. Fiercely defending creatures of burrow and glade.”