Smite

Smite is the summoner spell that defines the jungle role. It deals a large chunk of true damage to monsters, letting the jungler clear camps faster and, crucially, land the final blow on major objectives.

Because monsters like Dragon and Baron can be stolen by a single hit, contested objectives often come down to a Smite timing battle between the two junglers. Upgraded versions also grant utility such as healing or vision. Smite is functionally required for jungling, so almost every jungle-focused account will have it slotted, and it is rarely seen in any other role.