“ Animals have parasites and diseases, so do plants, there are even bacteria that cann dissolve oil spills or plastic or what have you - why couldn't there be a disease living off magic - a magic item could be infected, losing power and speading the plague to other equipment it contacts, while a magic user would slowly lose his powers and contaminate all he works with or casts a spell at...”
“ An insignficant little species, the candlebug (or waxmoth) is a persistent bane for mages and merchants alike. Each the size of a small digit, these little scarabs thrive on wax and burrow up inside candles, ruining them. Sometimes a late-night worker will hear a crack and a sizzle as his candle expires, only to find the half-burned remains of a waxmoth squirming around on his desk. This is very annoying in worlds where candles are expensive...”
“ Have a large room that elevates either up or down when triggering a trap. The floor can bring the players to new levels, where a mighty beast roams, or the floor flattens the players into the ceiling or drop into a pit of lava.”