Campfires

A Campfire is a three-block wide device. When standing near a Campfire (up to about 48 tiles away), a player's health regeneration is increased. This mechanic makes it a worthy addition to boss arenas. It is probably smart to have one of these in your hot-bar when going spelunking or into a dangerous place so that you can place it down quickly for some fast regeneration. It is also recommended to have one in your house, in case you're trapped inside with low health. It gives off a low amount of red light and smoke. Campfires do not work underwater after 1.2.1 update.

It is also used to cook a Marshmallow on a Stick.