SCP-058, or "Heart of Darkness", is an upcoming SCP in SCP: Unity that will be added in an as of yet unannounced update.
SCP-058 resembles a bovine heart, with four arthropod-like legs used primarily for movement, and four tentacles of adjustable length, covered with razor sharp spines. It has a single sharp 'stinger' on its rear, where the hole for the superior vena cava would be in a typical organ. SCP-058's tentacles can be "whipped" to a distance of 3.2 m at speeds in excess of 320 km/h. SCP-058 is extremely hostile and will use every opportunity afforded to it to inflict damage on its surroundings. SCP-058 has been shown to be highly resilient to trauma, and should be approached with caution even when apparently incapacitated.
SCP-058 is highly mobile and capable of rapid movement on both horizontal and vertical surfaces. It has been recorded reaching a speed of approximately 90 km/h in short bursts, covering distances up to 200 m, and has the ability to accelerate from 0 to 90 km/h in less than two seconds. It has been shown to use its tentacles for increased leverage and stability, as well as utilizing them to pull itself to other surfaces at high speeds.
SCP-058 'speaks' in a human voice, though no method of producing sound has been observed in its physiology. It speaks with vocal tone and accent of an elderly British male with a slight lisp and deep voice. SCP-058 talks constantly, regardless of conditions: even when attacking, SCP-058's voice and pace of speech are unchanged. The speech of SCP-058 lacks any detectable correlation to events, persons, or exterior locations involved with SCP-058.
SCP-058 is not currently in-game