“ 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”
“ Suppoki-
These creatures are desert animals that are much like huge, quadripedal sloths. They have a hide made of heavy scales to keep out gritting sand, and over that, a thick coat of fur.
During sandstorms, and when they sleep, Suppoki bed down in the sand, covering themselves up until they are miniature dunes.
Suppoki derive what sustenance they can from water sinks, dew, and underground insects.
Suppoki are often ridden by desert tribesmen. They are stubborn and slow, but are often the difference between life and death out on the sands.”
“ Pepperbox Wand
A typical wand with offensive capabilities (magic missiles, fire, fireball, lightning bolt) that was either damaged in combat or made just under par. When the wand is discharged, there is a 1 in 4 chance that it fires an additional 1d6 charges simultaneously or in rapid succession. Wands that shoot fire may incinerate innocents and friendlies, or burn whole buildings and even villages down. Those which shoot fireballs have a considerable radius, and lightning bolts that bounce upon contact with ground and stone can cause catastrophic random collateral damage. Those who have paid large sums for such a device may go seeking a refund, possibly even retribution.”