Ocean

Currently, the ocean acts as a barrier, and during Winter, a place for Pengulls to spawn before they hop onto shore. No living thing can cross the ocean, even flying mobs like Batilisks.

Objects that are situated on the coast very close to the ocean may drop their items in the ocean, and aside from bugged objects, they will fall into the water with a splash and be unretrievable.

Trivia

 * The Strange New Powers update added Pengulls that initially spawn in the ocean before moving onto the shore in Winter.
 * Shadow Creatures are able to cross into and out of the waters as they please,unless they become tangible when the player goes insane.