A low-powered, gimmick deck based around setting up Madkinesis Gothitelle- but with a hidden trick involving Toolbox Sigilyph, attaching as many damage-reducing Pokemon Tools as possible to create a shield that's nearly impossible to kill, while Gothitelle gathers energy on the bench. Having such a focus on this leaves the deck with poor flow and limited searching ability, though, so its weaknesses should balance it out from becoming too obnoxious.
Unkillable Sigilyph and a Gothitelle that converts energy into damage- but can fall apart quickly with bad draws and some counterplay. An interesting boss fight for casual decks of similar power.