“ The greatest tree in the woods has a secret, there is a dungeon under it made from the intricate web of roots. What creatures could reside here? What secrets will the PCs uncover?”
“ 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”
“ A large forest which is the site of a research monastery dedicated to Silence. In the course of developing new spells, the monks frequently deaden all sound in huge areas of the forest, an extremely eerie experience for anyone passing through.”