Once the P/T setting ability has resolved, that effect will override the native ability of Psyhcosis Crawler for as long as your Giganto-Crawler is on the battlefield
Typically, small sets are carried by one main chase card, with Phantasmal Flames being an outlier
The Field Spell Card, "Mementomictlan", gives further benefits to the theme as it gives "Memento" monsters the ability to prevent Spells and Traps from activating when they attack, targets a "Memento" monster that was destroyed to Special Summons a "Memento" monster from the GY with a lower level than the target, and the effect at the End Phase to set a "Memento" Spell/Trap card from the GY to the field, opening to a control playstyle with the Trap Cards
Each Set Booster contains 15 Magic cards, 1 Art Card, and 1 token, ad card, or card from The List (a special card from Magic's history-found in 25% of packs)