Special containment procedures: No person is to be admitted to SCP-XXX's containment cell without explicit clearance from SCP-XXX experimental oversight. In addition, SCP-XXX's passcode-lock function should be activated, and the passcode changed every 24 hours.
Description: SCP-XXX is a physically unmodified, jailbroken black 8GB Apple iPhone 3GS. It shows signs of heavy usage and unsanctioned repairs (see addendum 1). Testing has revealed that SCP-XXX appears to be unusually resistant, indeed possibly invulnerable, to deliberate damage. Given that ballistics tests of SCP-XXX would neutralise it if successful, those tests are still pending O5-level authorisation. SCP-XXX's onboard memory contains the standard suite of applications issued by Apple at the time of release. There is also one additional application, designated from hereon in SCP-XXX-A, which is the active component of this SCP.
SCP-XXX-A is an application whose title is 'Testing'; it is indicated by a black capital Beta on a white field. When activated, SCP-XXX-A displays a random English word or phrase, then returns the user to the home screen. This word or phrase appears to be associated with, possibly a title or codeword for, the effect that then occurs.
Activating SCP-XXX-A causes events to happen and states to be changed in the area of SCP-XXX, lending credence to the idea that SCP-XXX is the engine through which SCP-XXX-A operates (for a full list of anomalous events and changes of state during SCP-XXX testing, see Experiment Log XXX). The effect lasts until the phone is turned off (including by running out of battery), or is surrendered to another person. SCP-XXX can be recharged with standard iPhone charging equipment and appears to accept a standard battery, although due to its apparent invulnerability to damage and hence disassembly, this cannot be verified. Research is currently underway to determine what measures will be taken if and when SCP-XXX's internal battery is no longer viable.
SCP-XXX-A's effects do not apply to SCP-XXX, which has no anomalous features apart from those described above. However, running SCP-XXX-A on identical iPhones which are not SCP-XXX causes SCP-XXX-A to throw an exception and reboot the phone, with no apparent external effect.
Addendum 1: Analysis of non-user-facing data reveals that SCP-XXX is running a version of iOS which Foundation embeds at Apple confirm is not due to begin development until [REDACTED], possibly entailing an FK-class self-sustaining paradox.
Addendum 2: See Experiment Log XXX.
Experiment Log XXX
In all cases, experimentation was conducted by allowing a D-class or researcher to activate the application.
Test #0 // subject: SCP-XXX // effect name: N/A
Standard Foundation tests and specific protocols. Attempts to damage SCP-XXX with tools ranging from standard screwdriver to 2.5m broadsword; no effect. Containment cell designated; testing with D-class personnel approved.
Test #1 // subject: D-1/XXX // effect name: XYZZY
No apparent effect.
Test #2 // subject: D-1/XXX // effect name: Hello, Sailor!
D-1/XXX disappeared. A security alert was declared against a possible containment breach; however, security personnel using portable sonar equipment determined that D-1/XXX was still locked in SCP-XXX's containment cell. As of this writing, D-1/XXX remains wholly transparent, with an apparent refractive index of 1, but is otherwise fully tangible. Research into the mechanism of his invisibility continues.