These spectres use Ball lightning which deals lightning and chaos damage, an odd design choice... oh did i mention it has 5 sec cd (no fun allowed).

They also use spell called 'noodle beam' , a funny name, it deals pure chaos damage and has 10 sec cd ffs... Faster proj. is mandatory for them to feel somewhat okay at clearing maps. The cd's on their spells ruins these spectres, as you can see in boss room both spells are on cd and all they left is smacking boss with basic attacks. Another thing, when projectiles from Ball lightning reaches its max travel distance they stop and don't seem to expire unless you move 2 screens away.

My PoB https://pobb.in/tOk6QcpS7put

https://poedb.tw/us/Vivid_Watcher#VividWatcherHarvestSquidT3_

Get them from yellow crops in Harvest sacred grove.