A giant light bubble with electricity surrounding it.
The Thunder Shield (サンダーバリア,Sandā Baria?, lit. "Thunder Barrier"), also known Lightning Shield and Magnetic Shield (磁力バリア,Jiryoku Baria?, lit. "Magnetic Barrier"), is one of the shield variants in the Sonic the Hedgehog series that the player is able to pick up by breaking an Item Box with a lightning bolt or blue shield symbol on it. Like every shield, the player then becomes surrounded by a large bubble when obtaining it, with the Lightning Shield having electronic effects. The most known effect of Lightning Shield is to attract Rings that are close to the player like a magnetic force. In some games, the player is able to do double jump and even reject all electronic obstacles and energy projectiles that enemies are shooting at the player. Like the traditional shield, it can also absorb one hit without the player losing Rings or a life when touching enemies or obstacles.
The Thunder Shield was first introduced in Sonic the Hedgehog 3, as well as its locked-on form, Sonic 3 & Knuckles. Since then, the Thunder Shield has become one of the most recurring shield power-ups in the series. The functionality of the Thunder Shield has been varied only in a few games.
Sonic the Hedgehog 3 & Knuckles
In the first appearance on Sonic the Hedgehog 3 and its add-on continuation Sonic & Knuckles, the Thunder Shield is found in white monitors with a white thunder bolt symbol on it. After breaking the monitor, a huge electrocuted shield surrounds the player with a rotating effect on it. It has multiple features and it can be found in most of the Zones in both games. It can be also obtained from Bonus Stages, where it is found in golden gumballs with a B-letter on them.
In this game, the Thunder Shield absorbs one hit against enemies and obstacles, and magnetically attract Rings nearby in the Zone until they catch the fast moving player. However, if the player hits enemy or obstacle while Rings are attracted to the player, thus causing the Thunder Shield to vanish, the Rings will stop following the player and bounce everywhere and disappear after a while. However, the player can easily touch and run past Electric Generators in Flying Battery Zone and Death Egg Zone without harm with the Thunder Shield on. Exclusively, if the player is playing as Sonic the Hedgehog, by pressing , or during a Spin Jump, the Thunder Shield allows the player to perform a double jump.
Like the Flame Shield, the player will lose the Thunder Shield after touching water. When this happens, the water will flash for a split second, representing the electricity from the shield being dispersed in the water. Strangely, the shield is not lost when the player's character skims across the surface of the water in the Hydrocity Zone.
The Thunder Shield's (called Thunder in the Japanese version of the game) next appearance was in Sonic R, where it was yellow in color. It can be found on Item Panels on the tracks with yellow orbs on them. After obtaining a Thunder Shield, it will accumulate all Rings near the player. However, if the player falls into the water while having the Thunder Shield equipped, he/she will lose it.
Sonic R is the first game, where the Thunder Shield does not allow the player to double jump as Sonic, who is able to perform it in the game without needing the Lightning Shield.
In these games, the Magnetic Shield does not grant a double jump to any playable character while having it. However, like in previous games, it can attract nearby Rings by default and, like a normal shield, it absorbs one hit after the player touches any harmful obstacles or enemies. In Sonic Adventure 2, if the player runs through the Point Marker with over 90 Rings in hand, it automatically gives either a normal Shield or Magnetic Shield to the player.
Sonic Advance Series
The Thunder Shield (again referred to as the Magnetic Barrier) is featured in all three Sonic Advance titles. In these games, it can be obtained from item boxes that have a dark blue orb symbol on them. The appearance and effects of the Magnetic Barrier are the same as the ones presented in the Sonic Adventure games, meaning it can attract Rings nearby the player and absorb one hit when the player takes damage. However, it does not allow any of the playable characters in any of the three games to perform a double jump.
Shadow the Hedgehog
Magnetic Barrier later appears, along with Heat Barrier and a normal dark green Barrier in Shadow the Hedgehog, where it can be acquired as a power-up from containers or once again activated by breaking an Item Box with a dark blue orb symbol. It functions similarly to the Sonic Adventure games by attracting Rings to Shadow and disappears when the player gets hit once or falls into a bottomless pit.
Sonic Rush Series
The Magnetic Barrier also made an appearance in both Sonic Rush and Sonic Rush Adventure. In these games, the Magnetic Barrier's effects, appearance and means of obtaining it are almost identical to those seen in the Sonic Advance series.
In Sonic Riders and Sonic Riders: Zero Gravity, the Magnetic Barrier can randomly be obtained from one of the item boxes on the courses. When obtaining a Magnetic Barrier from an item box, it forms a temporary shields around the player that attracts nearby Rings.
In Sonic Riders: Zero Gravity, a Gear Part named "Magnetic Barrier" that is used exclusively for The Crazy and the Chaos Emerald allows the player to obtain a permanent Magnetic Barrier for the duration of the race. To activate this Gear Part, the player has to have collected a certain amount of Rings before handed. In Sonic Free Riders, a Gear Part that can be equipped named Ring Eater grants its user the identical abilities of the Magnetic Barrier seen in the previous Sonic Riders title.
In Sonic the Hedgehog (2006), the Lightning Shield appeared in the form of an ability called Thunder Guard. This ability can be activated using the Yellow Gem, which creates a yellow electric shield around Sonic. When activated, it attracts nearby Rings and can absorb one hit when the player takes damage. While it disappears after absorbing once, the Thunder Guard can be created again by using the Yellow Gem once more.
The Thunder Shield made another appearance in the Nintendo DS version of Sonic Colors where they can be found inside item boxes. In this game, the Thunder Shield's effects, appearance and means of obtaining it are identical to those in the Sonic Advance series and the Sonic Rush series.
In the console/PC version of the game, the Lightning Shield comes as both an equipable Skill, which grants the player a Thunder Shield once for each act, and an item box for Classic Sonic. Here, the Lightning Shield retains all of the effects it had in Sonic the Hedgehog 3 and Sonic & Knuckles, except that the shield does not disappear when the player goes underwater. There are also glitches where. if a player activates the double jump ability while jumping on certain springs, it would either bounce the player into an explorable part of the map with nothing in it or send the player falling into a bottomless pit.
In the console/PC version, the item boxes with the Thunder Shield appear exclusively in the Challenge Acts "Thunder Shield Challenge" and "With Your Powers Combined" where the player has use its effects to traverse the acts. The Skill for the Thunder Shield can be bought from the Skill Shop for 4,000 skill points after clearing the "Thunder Shield Challenge" and cost 70 Skill points to be equipped. To activate the Skill in gameplay, the player has to press /.
In the Nintendo 3DS version of Sonic Generations, the Thunder Shield's effects are the same as in Sonic Advance series and the Sonic Rush series. It can only be found in Act 1 of Emerald Coast. However, it can also be obtained as an extra skill by playing in Versus Mode online.
Sonic Lost World
The Thunder Shield make appearance along with other elemental shields in both versions of Sonic Lost World. In Wii U version, along with other power-ups and items, Thunder Shield is also obtainable power-up from the Miiverse, where players can share power-ups and items to each other via Miiverse. It has a dark yellow thunder bolt symbol and after getting the power-up, it creates a yellow orb with sparkling effects around it.
In Nintendo 3DS version of the game, it can be regularly found from item boxes with blue electrical orb symbol on them. Like in Sonic Advance series and the Sonic Rush games, it creates a blue electric shield around and attracts Rings nearby.
Through the whole series, Sonic is the only playable character, who has been able to perform the double jump with Thunder Shield and even he could only do it with the shield in two games. It then again, make progress to its own ability, which again Sonic has been able to do in Sonic R and Wii version of Sonic Colors.
When the player uses Sonic Boost in Sonic Unleashed, Sonic Colors and Sonic Generations, the move attracts Rings on near close of the player similarly like the Thunder Shield, which makes easier to collect them from group and string formats at high speed although the ring pull of the Sonic Boost in Sonic Generations is considerably weaker.
A humorous glitch involving the Thunder Shield can be performed in the Sonic Generations version of Rooftop Run. In Act 1, Classic Sonic can be controlled in 3D via a glitch using the Thunder Shield's double jump ability while being catapulted through a set of springs directly after leaving the front of the university. If you get a checkpoint while in 3D before dying (with at least 1 life left), the controls will become buggy, and the camera will be viewed similar to Modern Sonic's 3D sections.