Xavier Protocols - Anti-Phasing Gun

In accordance with the Xavier Protocols, a means of effectively neutralizing with extreme prejudice Shadowcat or any other entity capable of becoming incorporeal was designed to be used in case Kitty Pryde or someone else like her became of a threat necessitating extreme measure to deal with. First a highly flawed prototype and then a much more efficient second weapon was designed by Dr. Chase.

So far neither of the Anti-Phasing weapons have been used for their intended purposes of neutralizing someone capable of phasing but it has more than once been close to having to be implemented.

Mark 1 - The RBG (Really Big Gun)
Technically this could be used to neutralize almost anyone.

It is effectively a very heavy double barreled handgun with a six shot clip (of two projectiles each) in it and a spare clip stored beside it in the Institute's vault.

The key drawback of the RBG is that it is really heavy and requires someone with some form of super strength to properly use it. The few times the RBG has been removed from the vault with the intention of using it, it has been Pedro who did so.

The RBG utilizes the fact that phasing through a super dense material such as adamantium, vibranium, or osmium is very difficult to successfully do. When the trigger is depressed, a pair of adamantium coated osmium cored projectiles are propelled out of the barrels by a low grade explosive but not at exactly the same time, the intention is that the first projectile will cause the phaser to become partially corporeal out of shock and the second projectile will deliver the killing blow to the target.

ADDITIONAL NOTES:

In what could be seen as a bit of irony, the RBG is the Xavier Protocols response to the possibility of Pedro or Colossus going rogue.

Mark 2 - The APFD (Anti-Phase Frequency Device)
Effectively the weapon that utilizes the same principle behind the RBG in a form that is light enough to be used by almost anyone.

When the trigger is depressed, the target is almost instantly scanned to ascertain their phase frequency, which allows the APFD to release an energy balance of a counter phase frequency that upon contact with the target theoretically would return the target to at-least a semi-corporeal state allowing the second shot of high intensity plasma to deliver the killing blow.

The APFD was designed and built by Dr. Chase.

Unlike the RBG, the APFD is no more effective at neutralizing not phasing targets than a comparable energy weapon would be.