Xurkitree @ Electrium Z
Ability: Beast Boost
252 Sp. Atk/252 Spd./4 HP
31 IV's (All)
So I'm not quite sure why no one has suggested this strat yet, but I got the idea from BurlyGator's answer. But, instead of using Z-Hypnosis, which only has 60% accuracy, Z-Electric Terrain also boosts speed, but obviously doesn't miss, and also boosts the power of Xurkitree's Thunderbolt. Energy Ball is a solid move with a chance to lower Special Defense, (which shouldn't matter since the opponent will be knocked out) but more importantly, it covers Xurkitree's only weakness, Ground. Finally, I chose Signal Beam over Dazzling Gleam because once it has a few Beast Boosts, the 5-point base power difference won't matter too much, and it could also possibly confuse the target. Also, a lot of people chose to run tail glow, but honestly, Electric Terrain Thunderbolt is already boosted by two stages, essentially, because of the electricity on the field and because it's a STAB, which should allow you to get a KO, where it only gets easier from there.
In my opinion, this has worked really well for me, and while it may not have as much coverage, it has more power than any other version of a competitive Xurkitree, more options than any scarfed ones, and it's also more reliable.