SCP-505, or "Ink Stain", is an upcoming SCP in SCP: Unity that will be added in an as of yet unannounced update.
SCP-505 is a Model ████ Faber-Castell fountain pen, produced in 2001. It is identical in all respects to a standard fountain pen apart from its association with SCP-505-1. SCP-505-1 is the black ink produced by SCP-505, which exhibits the property of self-replication. SCP-505-1 spreads at a variable rate, affected by the substance it comes into contact with and the amount of SCP-505-1 present. Quantities of SCP-505-1 have been shown to increase at rates between 0.5 and 540 mL per second. Standard ink-removing chemicals are able to partially remove SCP-505-1 and inhibit its spread; however, sodium hydroxide is necessary to remove SCP-505-1 contamination completely, and has shown to be ineffective in environments with particularly high SCP-505-1 concentrations. Fortunately, the growth rate of SCP-505-1 appears to be inversely proportional to its quantity at high concentrations. Whilst the observed effects of this are negligible in most cases, this inverse growth phenomenon provides the only explanation for the partial containment of SCP-505-1 despite a number of cases of large-scale environmental contamination which were projected to otherwise lead to an NK-class end-of-the-world scenario.
SCP-505 is not currently in-game