Luden's Echo 226655since 13.14.1 10 changes
3000g (3000g base, 2100g sell)
Echo: Damaging Abilities deal magic damage to the target and 3 nearby enemies and grants you Move Speed. Dealing ability damage to Champions reduces this item's cooldown.Mythic Passive: Grants all other Legendary items Magic Penetration.
Builds into: 
Force of Arms
SpellDamageManaCooldownReductionAbilityHaste
Click any two patches to compare; the current range is shaded.
− (0s)Damaging Abilities fire 6 Shots that deal bonus magic damage to the target and nearby enemies. Remaining Shots fire on the primary target, dealing 35% damage.
+ Damaging Abilities fire 6 Shots that deal bonus magic damage to the target and nearby enemies. Remaining Shots fire on the primary target, dealing 35% damage.
− Damaging Abilities fire 6 Shots that deal bonus magic damage to the target and nearby enemies. Remaining Shots fire on the primary target, dealing 35% damage.
+ Damaging Abilities consume all the charges to deal an additional magic damage to the target and one additional nearby target per charge. If there are insufficient targets in range, for each remaining shot, repeat the damage on the primary target.