Its a spark glitch, most likely. I don't use mods, and I did have Brionac charged with spark (I had gone afk, and switched out Brionac with my Wooden Blade so Brionac wouldn't lose Durability.)

or a mod? could be a spark glitch

Who knows? I thought it was fully. Like the Ice spear glitch, where there's little fragments of ice floating around my ice wand's tip, and when I switch weapons, the ice is still floating around, in relation where the tip of my wand would be.

The wood is probably wet otherwise it wouldn't conduct electricity? =P