pyramid shaped weights
Inside the chest were five golden pyramid shaped weights. They are mostly lead, but enough gold in the weight and chain to bring $2000 each. Each weight has some unnatural looking rune like carvings. They are not like the magic sigils the mages wear, these seem unwholesome.
The carvings do not correspond to any known runes, or alphabets.
From what you have seen, there were 12 unique symbols, with some repeats on some of the pyramid faces.
For example: if the symbols represented numbers, the sequence on one weight might be 1, 4, 5, 7. On another 2, 4, 6, 8.
The primitive islanders also had 5 sets of weights and chains in their possession, but they were made of a different material. Perhaps stone. (You did not examine closely)
What do they do?
The weights thrown into the sea by the islanders:
- summoned many fish.
The weights tossed in by Chris:
- summoned a gargantuan sea creature
- boiled the water in the lagoon
- summoned a huge chest full of gold
In both cases, the weights were thrown in on a full moon.