Disclaimer: Star trek is owned by Gene Roddenbury/Paramount. Spike is owned by Joss Whedon/Fox.
This story is a response to challenge 1805 "Spike Trek", or to be more accurate, it's a response to a typo in challenge 1805. For some strange reason, I couldn't find this one in the open FFA pairings...
Stardate: 234123.3, just after tea.
Normally when the ship went to red alert, sirens sounded throughout the vessel; however, in this case the alert was due to an intruder that sensors had detected in the captain's ready room. The senior officers had been quietly notified and a security detail was stationed outside the room awaiting further instructions. Meanwhile, the command and control functions of the ship had been re-routed to the battle bridge in the aft section, which was where Captain Picard and Commander Data now found themselves.
"What can you tell us about our uninvited guest, Mr Data?" the Captain asked.
"Genetically, for the most part, he appears to be an adult human male, but there are a number of anomalies. His face has pronounced ridges, and his incisors are elongated. His eyes are yellow, and the pupils bear more resemblance to a member of the feline family than an ape. Also, he does not appear to be breathing, and his body does not radiate any heat."
"Have you found any matches in the database of known species?"
"None, sir; however, his appearance does correlate to the characteristics prescribed in popular mythology to a vampire."
"As unlikely as it may seem, it is the only hypothesis I have at this time, given the available information."
"Okay, so what is he doing in my ready room?"
Data looked at his superior officer; despite his lack of emotions, he still felt uneasy answering that particular question.
"Well, sir, it appears that he is copulating with your desk."
Challenge 1805 as it was at the time of writing: "I would like a story where Spike is in the Star Trek NG universe and temporarily on the Enterprise. Spike has has an affair with one of the offices on board. Worf would be my first choice but Riker, Data, or the Captain are fine also."