The Mimic/Strategies - OSRS Wiki

Upon completion of an elite or master clue scroll, the casket received has a chance of turning out to be a mimic chest. Mimic caskets can only be obtained from an elite or master reward casket after asking the strange casket to enable the chance to obtain a mimic casket (which is disabled by default).

Treasure Trails - OSRS Wiki

Clue scroll (medium) - OSRS Wiki

Amulet of power - OSRS Wiki

Loot from trying to get 1 mimic : r/2007scape

Ethereal Perceptive - OSRS Wiki

Radagon of the Golden Order

Clue scroll (easy) - OSRS Wiki

Arcane spirit shield - OSRS Wiki

OSRS' Treasure Trails Update: Mimic Boss Changes, Beginner Scroll Clues, Stackable Caskets and More

Can I do mimic? : r/2007scape

Magus ring - OSRS Wiki

Cerberus - OSRS Wiki