250mm Strike Cannons
From Liquipedia Starcraft 2 Wiki
The 250mm Strike Cannons spell causes the Thor to begin channeling a bombardment of a single ground target in 7 range with the strike cannons on its back with a 2 second start-up and wind-down time dealing 500 damage over 6 seconds while stunning the target - disabling all operations of the targeted unit including attacks, research, and movement - for a total of 10 seconds provided the Thor is not interrupted. Moving out of range will abort the spell.
The spell specifically deals 25 damage every .24 seconds on intiation for 20 hits and stuns at the initiation of damage.
Since the Thor is totally helpless while channeling and deals the same amount of damage without the spell, it is very rarely used or researched. In most scenarios units can even maneuver out of range before it is operative. The spell damage quickly destroys Immortals, however, and the stun can have limited utility.
It can nonetheless be used in Zerg and Terran matchups to quickly destroy bases while disabling them. Three Thors (e.g. dropped by Medivacs) can take down a Hatchery or Command Center within 10 seconds. Four Thors are required to destroy a Nexus or Lair.
The 250mm Strike Cannons can one-shot-kill the following units and structures:
 Vs. Protoss
250mm Strike Cannons are a good way of killing Immortals. Since the damage received is considered Spell damage (like Yamato Cannon), neither armor values nor the Immortal's Hardened Shield apply, and the Strike Cannons will kill an Immortal.
250mm Strike Cannons are also useful when dropship harassing with a single Thor, as they can kill a Pylon very quickly. This may be used to render a crucial building unpowered, though with one vehicle weapons upgrade and target fire this ability is irrelevant, and should be used only to avoid Feedback damage if High Templars are in play.
 Vs. Terran
Thors are part of some successful late game compositions. They excel against Vikings, if they are clumped, as well as on the ground. However, they lose handily to Battlecruisers, making them only a compositional boon, and not a staple or necessity in late game play, especially given their high supply cost.
 Vs. Zerg
Since 250mm Strike Cannons should only be used on "bigger" targets, they are limited to taking out Ultralisks and buildings. However, as of patch 16, Ultralisks are natively immune to the stunning part of this spell. Although this does not exempt them from taking the armor-ignoring spell damage, they can be moved out of the 7+4 range in order to dodge the full barrage and abort the Thor's channeling.
- Can be used against buildings.
- Can be used against neutral units/structures such as Destructible Rocks.
- A stunned target is unable to move, attack or use abilities. This includes using transports, (defensive) buildings and any research or production taking place in them.
- The range of 7 is equal to the Thor's ground attack range.
Since the DPS of the 250mm Strike Cannon is 50 (500 damage over 10 seconds), getting a Level 1 Vehicle upgrade will enable the Thor to have a greater Ground DPS than the Cannons (46.9 + 4.7)
 Patch Changes
|Patch 11 (version 0.13.0.15250)|
|Patch 17 (version 0.20.0.16036)|