Mare Sargassum
This is an escalation found by completing Desolate Site anomalies. It may contain up to four parts, each of which will be about 4 jumps from the previous system. The first three will be in high-sec space, while the fourth will be in low-sec.
The sites do not have gates, and can be easily completed in a cruiser.
Part 1
A few small drones, and one sentient drone. The escalation appeared after I killed a few of the drones - and before killing the sentient drone (timer?). Strain infester alvi warp scramble/web.
Part 2
Similar to first, killing sentient drone first triggered escalation. There is at least one reinforcement wave.
Part 3
Fewer rogue drones, and killing the sentient drone once again triggered the escalation. As a bonus, you get to see a great big red cube in space. The Borg turned more evil?
Part 4
This part will be in a low-sec system.
(took me two jumps in). 5 small rogue drones waiting on warpin, and 5 "Drone Hold" cans. Completion popup happened after blowing up the first wave and starting to open cans. Strain Splinter drones can warp scram and web, they should be priority. Two reinforcement waves later appeared, with a Rogue Mining Overseer dropping T2 salvage (as loot?). One of the Drone Hold cans contained some drone goo (Dark Compound, Condensed Compound), but overall fairly worthless stuff (Confirmed).
Rewards
Each part has a commander rat which, when killed, will drop T2 salvage and Rogue Drone components. Lootable cans may contain drone alloys.