A hostage is a person or entity which is held by a captor. They are often held for the purposes of ransom or to keep them from interfering.
The mutant Pyro and Blob took hostages at the Deep Space Observatory by creating a cage of fire. The X-Men flew in the Blackbird to the Observatory while Pyro was acquiring the tracking coordinates for the Scorpio Comet.
The X-Men arrived and Colossus attempted to attack Blob without success. Pyro attacked the heroes but Storm countersed with wind. When the fires died down there were no sign of either villain. Police showed up outside so the heroes left before they were blamed for the attack.