You can banish 1 "lswarm" monster from your Graveyard, then target 1 "lswarm" monster in your Graveyard
but is far from the hardest thus along side the "non-activation" effect this can just take an entire board uninterupted Yakamaru: currently there only 1 card in this game that can trigger the summon effect being Atlantean Dragoon
Table of Contents show What Are Witches in MTG

Set Contents Monster Zefraath UR3 Secret dragon star - Sephira bull N2 Treasured Dragon Star Sephirahushi N1 Symphonic Warrior Guitaar N3 Symphonic Warrior Guitaar Squirrel N2 Symphonic Warrior Miccs N1 Psychic Heavy Warrior Bai-Q N3 Psychic Heavy Warrior Ten B-N N1 Psychic Heavy Warrior Wakar U4 SR3 Psychic Heavy Monk Big Ben K R2 Psychic Heavy Samurai Equip Ru Iwatooshi N1 Superheavy Samurai Soulpeacemaker R1 Psychic Heavy Samurai Armor Gaia Flareon N1 Sokenshi Taia N1 Phantom Orion R2 Ash Blossom & Joyous Spring SR3 Maxx "C" SR3 Magic Zefra Providence R1 Oracle of Zefra N1 Called by the Grave SR2 Crossout Designator SR1 Traps Nine Pillars of Yang Zing R1 Zefra Divine Strike N1 EX Baronne de Fleur UR1 EX Baronne de Fleur UR x1 Accel Synchro Stardust Drago SR1 Shoufuku N1 Evil Dragon Star Gaiser R1 Genryuusei Boutenko R1 Gear GigantoX N1 Psychic Heavy Warrior Kakar C N1 Qliphort Genius SR1 Barricadeborg Blocker SR1 Auroradon SR1 Heavymetalfoes Electrumite N1 Sorcerer of Locus SR1 S:P Little Knight SR1 Divine Bow of Calling - Apollousa UR1 #GATCHA Deck Item ID: 252558517

First of all, we have Final Fantasy VII's Yuffie Kisaragi as a reimagined Yuriko, the Tiger's Shadow
As the chain builds, card effects do not resolve until both players agree they are done adding to it, at which point each effect in the chain resolves in backwards order, so the last card played is the first to resolve