Friday Encounter: The Island Fish

Sinbad: Legend of the Seven Seas

Here's an encounter to bring one of my favorite tropes in folklore and mythology to the table. It should be used while the PCs are traveling by boat, preferably on a voyage through a relatively uncharted body of water.

While traveling the open sea, the PCs come across a small island that is not marked on any of their maps. The ship's crew has grown tired over the long journey, and they petition the captain to stop and rest here, perhaps foraging for food to replenish their meager rations. If the ship's captain is an NPC, they agree to moor the ship here; if they are a PC, that decision is up to the player(s).

If the ship docks, the crew wishes to spend the night on the island, and they suggest the PCs explore before sun sets. PCs exploring the island will find that it is mostly flat and rocky, covered in sparse shrubs and grass, with a few short trees here and there. There are no land animals native to the island, but a few seagulls can be found, and there are some crabs on the shore. The island is 160 feet long and 100 feet wide, with a circle of rocks and trees at the center of the island forming a natural campsite, 80 feet from the ship. Keep track of how far the party ventures into the island - it will become important later.

At nightfall, the ship's crew will make camp at whatever suitable spot the party found, and make a fire from some driftwood and fallen branches to cook some birds and fish they were able to catch. However, this is where the island reveals its secret. The "island" is in fact a gigantic fish that has laid dormant here for years, and over the ages, enough soil has built up on its back to form solid ground. However, when a fire is lit, the fish will wake up, and seek to retreat into the water - with everyone still on it! The fish will also wake up if a fire is lit on the island before the crew does, or if the PCs make any extremely loud noises (such as that of an explosion).

Once the fish wakes up, enter Action Time. The fish takes a turn at the beginning of initiative order every round. On its turn, the fish always sinks two feet into the water. The PCs must use this time to run back to the ship before they sink with the fish! If they make a move or dash action, they must make an Acrobatics or Athletics check (whichever best fits the action); on a failed check, they can only move at half speed that turn due to the rising water. The DC for this check starts at 5, and increases by 5 for every two feet the fish sinks after the first. If any PC is below the water (this would typically be when the fish has sunken six feet for a medium-sized creature, or three feet for a small one), they must swim to their destination, and they must hold their breath unless they have some means of breathing underwater.

You don't need to roll for the crew during this part - you can just assume that enough redshirts drowned to make things suitably dramatic, but enough survived that the ship is still in working order. However, if there are any named NPCs on the ship, you may wish to have them act during the initiative order like the PCs, following the same rules.

If you so desire, you can add other obstacles to overcome during the run to the ship if you want make the encounter more challenging. Do not forget that, although most parties will likely run for the ship, other courses of action are possible and should be allowed according to the DM's judgment. If anyone in the party is able to communicate with the fish, for instance, they may be able to convince it to take them to their destination - though the fish will likely demand something in return.