Essence

If you are looking for essence that is dropped by Golems, look here.

Essence is identified as a glowing, yellow spherical ball of energy that can be harvested, rewarding the harvester experience points (abbreviated as EXP). Each essence gives 10 Experience Points.

Essence is somewhat like the physical form of EXP

The essence orbs themselves have no friction and seem to roll around quite freely, similar to the Spirit Key. They share the properties with items such as mob drops, and can in fact be placed in Chests.

Details
The only way to obtain essences is by destroying or killing the following forms of life, objects, or entities: When it is picked up by the players, it will not take up any inventory spaces and cannot be carried as an item.
 * Ancient Tree
 * Giant
 * Wealthy God
 * Miserable God
 * Hateful God
 * Lonely God
 * Old God
 * Spirit Shelly
 * Sun Tree
 * Shelby
 * Sheldon
 * Queen Ant (currently removed)
 * Magnetite, Essence &amp; Emerald Chests

The only way to move essence is by holding left click on it and transporting it to a new place.

You can still buy essence chests in Classic Booga Booga

However, if the bag is deemed as 'full', the Essence cannot be picked up unless the player finds a way to reduce the number of items in their inventory. This has been proven bugged and is still a problem.

Essence Chest
Before the Mojo Update, it was possible acquire Essence from essence chests. You could purchase essence chests in the chests menu. Now it can obtained through the purchase of Emerald & Magnetite Chests.

Trivia

 * Essence has a very similar appearance to Sun Fruit and spirit key.
 * Before the Void Update, Essence only gave you 5 EXP, but was changed after Soybeen read a comment begging for him to buff the Ancient Tree.
 * Essence was common in the Emerald Tools Update, due to hackers (or simply players with a lot of robux) spamming and dropping Emerald, Magnetite, and Essence Chests. This has stopped now due to all coins being wiped in the Mojo Update.
 * Essence highly resembles the Spirit Key in shape and texture.
 * The Ancient Tree gives a lot of essence, but it may not be worth your time to cut it down if your tool of choice will take a long time to chop it. Now the Ancient Tree will give you about 6-20 levels if you are below level 90.
 * The sun island is the one of many ways to grind Essence because Sun Trees drop Essence, and there is other things you can farm over there as well. The sun island gives 175 exp!
 * Another way to grind Essence is on the first sky island. There are several Feather Bushes on the island. They drop 1 Essence, are easy to break, and respawn fairly fairly fast. (the feather bushes as of right now do not drop essence)
 * Essence gives 10 exp to lvl up to lvl 100 you need to gain 6825 exp or 683 essence.