Stormchaser is a unique Scutum from Diablo II: Lord of Destruction.
A rather strange shield, Stormchaser has high defense and a mediocre chance of blocking, but is notable for its seemingly arbitrary (but similarly-themed) bonuses.
As its name implies, Stormchaser has a variety of weather-themed properties. It has a chance of casting Tornado or Blizzard upon being struck. Although both are powerful spells, neither have a very high chance of being cast, and even if they are, neither are high enough level to be effective enough to kill enemies.
However, Stormchaser is meant to be used by physical fighters. It gives a sizable boost to Attack Rating, as well as a fair amount of added Lightning damage.
Although it gives a bonus to Lightning Resist, Stormchaser is still not necessarily the best option defensively, since it doesn't give bonuses to all resistances. For a character more concerned offensively, this may be negligible, but otherwise it may be wiser to find a more defensive shield.
Stats[]

Stormchaser
Scutum
Defense: 161-198
Required Level: 35
Required Strength: 71
Durability: 62
Chance to Block:
Paladin Smite Damage: 11 To 15
+160-220% Enhanced Defense
+20% Increased Chance to Block
4% Chance To Cast Level 5 Tornado When Struck
4% Chance To Cast Level 6 Blizzard When Struck
10% Faster Block Rate
+150 To Attack Rating
Lightning Resist +50%
Half Freeze Duration
Adds 1-60 Lightning Damage
Normal Shields — Pelta Lunata (Buckler) • Umbral Disk (Small Shield) • Stormguild (Large Shield) • Steelclash (Kite Shield) • Swordback Hold (Spiked Shield) • Bverrit Keep (Tower Shield) • Wall of the Eyeless (Bone Shield) • The Ward (Gothic Shield)
Exceptional Shields — Visceratuant (Defender) • Moser's Blessed Circle (Round Shield) • Stormchaser (Scutum) • Tiamat's Rebuke (Dragon Shield) • Lance Guard (Barbed Shield) • Gerke's Sanctuary (Pavise) • Lidless Wall (Grim Shield) • Radament's Sphere (Ancient Shield)
Elite Shields — Blackoak Shield (Luna) • Stormshield (Monarch) • Spike Thorn (Blade Barrier) • Medusa's Gaze (Aegis) • Head Hunter's Glory (Troll Nest) • Spirit Ward (Ward)