Pulses of bright light flare up from within the strange crystals. Any creature adjacent to a crystal gains resist 1 damage!
A school of cave fish draw your enemies attention with their chaotic splashing. Monsters grant combat advantage!
The slick floor allows daring PCs +2 to speed & they must make an Acrobatics check DC 10 or fall prone at the end of movement!
Cold mist from the waterfall deeper in the cavern soaks the party; The PCs gain resist acid 3 but take a -1 penalty to speed.
Ghosts of the past provide hidden insight. PCs gain a +4 bonus to untrained skill checks!