Blizzard has been teasing something related to StarCraft II over the last couple of days.
It's likely that the company is preparing to reveal the final Protoss themed chapter in the StarCraft II trilogy, entitled Legacy of the Void, at BlizzCon this weekend.
It has been two years since the last expansion, the Zerg themed Heart of the Swarm.
The teases are in the form of short audio clips shared over Soundcloud. Two have been uploaded so far, and are called "See" and "...you..."
Presumably there are more teasers to follow.
Any major announcements from Blizzard will be made during BlizzCon's opening ceremony. It will be streamed free at www.blizzcon.com, at 8am, Saturday, November 8, NZDT.