Anirrum is generally obtained by using two reticula in a corpsepitcher. Various items can be dipped in it to transmute it into its anirrum counterpart.

Ingredient	Product
Deepslate Altar	Anirrum Altar
Deepslate Podium	Anirrum Podium
Iron Ingot	Anirrum Ingot
Iron Equipment	Anirrum Equipment
Netherite Ingot	Charonite Ingot
Netherite Equipment	Charonite Equipment
Soul Lantern	Anirrum Lantern
Iron trimmed equipment	*Anirrum trimmed equipment
Netherite trimmed equipment	*Charonite trimmed equipment

* Please note that if you have a trim present on iron or netherite equipment, upgrading the trim will take priority over upgrading the equipment.
** Additionally note that not all corpsepitcher recipes are listed.