This is a sea encounter that was introduced in publish 71, July 2016. It requires special items from the fishing quest to start, the Oracle of the sea 
and 
Charybdis bait. From publish 106, Autumn 2019 these two items can also be crafted, the Oracle by a tinker and the bait by a cook, however they still require rare ingredients, obtainable from Ancient SoS chests.
When used the Oracle will identify a random location somewhere on the same sub-server (excluding the Cove, Minoc, Wrong area where there is insufficient deep water), this location is good for 1 hour. The oracle must remain in the fisherman’s pack for the location to remain valid. Locating the monster consumes a charge, fish oil made by a cook, can be used to re-charge it.
A fisherman of grandmaster or higher skill has a 25% chance of summoning Charydbis when using a fishing pole with Charybdis bait and having the Oracle in his pack, however success will almost certainly prove fatal to the character.
This creature has no slayer vulnerability and is immune to barding but can be damaged by cannon fire. He spreads tentacles around the boat which damage the boat, cast spells on the crew and will do area damage if they are near enough. A substantial number of crew members will be needed if you are to succeed in this encounter. A Britannia boat is highly recommended, also, if available, an Orc ship; this being capable of doing higher cannon damage. Frost cannonballs are also believed to be effective.
From time to time he will cast a powerful wave of water that pushes your ship causing damage, you have no control over the ship during this event and can not escape it.
The fisherman has a guaranteed drop of an item of Virtuous or Villainous armor, in addition the corpse will contain rare fish steaks as well as gold and some magic items. New rewards were added during publish 106