We report the discovery of an object near M87 in the Virgo Cluster with an extraordinary blueshift of -1025 km s ^ { -1 } , offset from the systemic velocity by > 2300 km s ^ { -1 } .
Evaluation of photometric and spectroscopic data provides strong evidence that this object is a distant massive globular cluster , which we call HVGC-1 in analogy to Galactic hypervelocity stars .
We consider but disfavor more exotic interpretations , such as a system of stars bound to a recoiling black hole .
The odds of observing an outlier as extreme as HVGC-1 in a virialized distribution of intracluster objects are small ; it appears more likely that the cluster was ( or is being ) ejected from Virgo following a three-body interaction .
The nature of the interaction is unclear , and could involve either a subhalo or a binary supermassive black hole at the center of M87 .