Not to be confused with Seashell, a vanilla item found in the Ocean.
The Sea Shell is a Pre-Hardmodeaccessory dropped by Sea Snails in the Ocean biome. It increases defense by 3 and allows free movement in liquids. Standing in a liquid increases its bonus by 3 defense and additionally gives +5% damage reduction and +15% movement speed.
If the player is patient enough to travel to the Ocean and farm Sea Snails, the Sea Shell is a great accessory to use for your first boss battle, as it can provide up to a maximum of 9 defense with the Warding prefix.
Additionally, the Sea Shell's ability to mitigate water physics can help the player navigate large bodies of water before they obtain important mobility items.