A large bamboo like plant grow on a shoreline. Rather than growing round like conventional bamboo, this type of grass is shaped more like celery, and mature stalks just need the ends trimmed for ready made canoes.
A race of beings actually IS invunerable while in adolecence. They age, but cannot be killed. A miniority of the race (1 in 20) does not become invunerable, but rather becomes immortal at some point in thier adolecence, and ceases aging while being vunerable to death in all the normal ways. Another minority (also 1 in 20) Permanatly becomes invunerable after adolecence, but ages twice as fast as the race normally does. There is no known way to test for which of the three traits an individual manifests and the three traits cannot mix, as they are tied to the same gene, as it were.
A certain type of demon cannot not be hit by ranged weapons or attacks. Attacks have to be made up close and personal for the damage to mean something. Ranged attacks are to impersonal.
Possibally a way to make the ranged attacks more meaningful would be to coat the arrow head or what not with the shooters blood. Of course, they'd better be a good shot, otherwise they're wasting arrows and already bleeding to boot.
Spells: wizards might have half or no effect, preist might work due to divine intention.
The PCs have travelled long and far. As nightfall approaches a mighty storm is unleashed. Luckily there is a lush wood nearby the path.
A good shelter for the rage of the unnamed weather gods it seams at first. As the PCs enter under the roof of this dense wood, they are welcomed by only a few drops wich is allowed trough the thick forest crown. A fire is offcourse required to warm the weary bones of the travellers. As one of the party is set to the task of collecting firewood the others settle down at a suitable location. But alas, they did not know the perils of this forest. But it seems clear to the rest of the party that something ill is at work as the woodcutters scream echo from afar.