Spell shield

Note: Not to be confused with magic shield.

General

Spell Shield example — Sivir protecting herself with Spell Shield.

The health bar usually has this purple frame to indicate the Spell Shield status.

A spell shield refers to one of several effects that have the capacity to negate hostile abilities from applying to the recipient.

The shielding can vary per case with other included mechanisms such as on-hit effects and subsequent targeting ( Bouncing).
Spell shield negates effects coming from champion abilities, monsters, champion summoned units, items, and a select few runes but not summoner spells and persistent effects from AoE DoT and passive DoT effects unless otherwise stated.
Multiple active spell shields over a single unit will break simultaneously if the triggering hostile ability does not have a crowd control effect. This is intentional.
Spell shield takes priority over damage shields, crowd control immunity, displacement immunity, and slow immunity.
Dragons' attacks can be blocked, but their knockback upon taking damage cannot.
Abilities applying multiple instances of damage (e.g. Boomerang Blade, Blooming Burst, Unleashed Power) will have a single instance of their damage prevented.
Some abilities that have already applied onto the target (e.g. Death Mark, Sleepy Trouble Bubble, Umbral Trespass) do not get blocked.
Some empowered basic attacks will also trigger spell shield (e.g. Chomp, Power Fist, Ruthless Predator) but the damage being blocked, either total, bonus, or none, is case by case.
Terrain displacing abilities (e.g. Crystallize, Pillar of Ice, Weaver's Wall) cannot be blocked.

Single ability

The following will block one enemy ability, with precedence given to the ability spell shield. If the ability is of an enhanced basic attack (e.g. Harsh Lesson, Power Fist) the spell shield will not block the damage of it, but only any additional effect it might have, like crowd control. In the case of Harsh Lesson, the spell shield breaks even if the attack doesn't have any crowd control effect with it.

Champion abilities

Items

Patch History

Unknown patch

Spell shield no longer blocks multiple hostile abilities if they struck at the same time the shield breaks. However, all hits will still be blocked if they come from the same ability (i.e multiple Azir's Soldier hits; Illaoi's Tentacle slams).

Alpha Week 2

Added with the release of Sivir.

Gameplay Elements

Targeting Types	Auto (Passive · Self) · Direction · Ground · Unit (Collision · Radius)
Unit types	Champion · Minion · Monster · Pets · Structures (Turret · Inhibitor · Nexus) · Terrain
Effect types	Ability effects · Attack effects (On-hit) · Area of effect · Damage over time · Heal · Multi-hit · Redirected damage · Shield · Single-targeted
Ability types	Aura · Blink · Buff · Combat status · Crowd control · Damage (Ability · Basic · Magic · Physical · True · Nexus Obelisk · Execution) · Dash · Debuff · Invulnerability · Pet · Sight · Spell shield · Untargetability · Ward