Rod of Ages 226657since 13.14.1 8 changes
2500g (2500g base, 1250g sell)
Timeless: After 2 combat rounds, this item gains an additional 0 Ability Power, 0 Health, and 0 Mana, and you gain a level.
Eternity: Taking damage from champions restores 7% of premitigation damage as Mana. Casting an ability heals for 25% of Mana spent, up to 20 Health per cast, per second.
Cooldown (RodOfAgesDummySpell): 0/0/60/60/60/60/0
Builds into: 
Infinite Convergence
HealthHealthRegenSpellDamageManaManaRegen
Click any two patches to compare; the current range is shaded.
− After 2 combat rounds, this item gains an additional 0 Ability Power, 0 Health, and 0 Mana, and you gain a level.
+ After 2 combat rounds, this item gains an additional Ability Power, Health, and Mana, and you gain a level.
− After 2 combat rounds, this item gains an additional Ability Power, Health, and Mana, and you gain a level.
+ After 2 combat rounds, this item gains an additional 40 Ability Power, 200 Health, and 200 Mana, and you gain a level.
− After 2 combat rounds, this item gains an additional 40 Ability Power, 200 Health, and 200 Mana, and you gain a level.
+ After 2 combat rounds, this item gains an additional 50 Ability Power, 300 Health, and 400 Mana, and you gain a level.