Sealock Monster

Stuck somewhere between a kraken and a giant octopus, sealock monsters are not the deadliest of the strongest, they aren't clever or favored by Thassa. But sealock mnosters are one of the most dangerous creatures for those who live along the coastline, where sealock monsters wander once each season, coming up from the depths to nest in the deep caves hidden amongst the rocky shores.   Seasonal Terror Like the tides they command, the arrival and departure of sealock monsters from Theros's shores are a cyclical affair. Once each season the creatures rise from the depths, pulling waves with them, flooding any unfortunate low-lying structures and crashing small boats against the rocks. Once a sealock monster is as cloose as possible to the upper shore, it pulls itself onto the sand and begins to search out a nest for itself. Just like octopi, sealock monsters have no interior skeleton, giving their land-based movement and unnervingly fluid appearance and letting them search every nook and cranny for the perfect hiding place. Once there, the monster lays its eggs in a shallow tide pool (often one of its own creation) and then departs once more. The eggs will take the rest of the season to hatch, and in the meantime, the sealock monster will remain in the water during the day, fighting off anything it deems a threat that ventures to close to the nest. At night, the sealock monster returns to the chosen cave, to rest and watch over the clutch, as well as prepare the environment for its young, stockpiling prey and using its muscular tentacles to slowly shape the surface of its hiding place to its liking.