Reach the secret room where you get the Alchemy Coin in the "Explodatorium" level. This room has six enemies in a narrow corridor at the bottom, with a lone Greenarmor above. Drop down and use your relic when at least five enemies are clustered together. If needed, leave the room and re-enter to try again. Reach the area with several Propeller Rats in the "Pridemoor Keep" level. Move around until you get five of them near you. Note: This may require a few attempts. To retry, scroll out of the area and return to force the enemies to to respawn.