The Relaxer

A chair that you can rest on that increases SP recovery by 50% and heals 50HP every 10 seconds, which is not affected by Warrior's Improving HP Recovery. Suggested that it is replaced with the sit button.
If hit by a monster while resting, the chair will be retracted back to your inventory, you will get knocked back and you will recieve the appropriate damage.
Unfortunately, since you can only get this from Pio's Collecting Recycled Goods quest which is in Maple Island, if you forgot to do that quest (or if you're an old player and this quest was not released when you were in Maple Island) then as of now there is no way to get the chair, keeping in mind that the relax chair is non-tradable.