Mega Gengar

Shadow Tag prevents all trapped opponents from switching out. The entire perish trap strategy depends on this ability. Perish Song KOs all active Pokémon after three turns; combined with Shadow Tag, opponents cannot switch to clear the Perish count. Substitute creates a protective buffer while the turn counter ticks down. Shadow Ball provides Ghost STAB for turns when offense is needed. Timid maxed Speed ensures Mega Gengar acts first to establish Substitute and Perish Song before disruption arrives. The team's entire win condition flows through this one trap sequence. Incineroar and Sinistcha exist to keep Gengar alive long enough for the three turns to expire.