Rune Types and What They Do
Mine Cells uses several rune items to gate and unlock content:
Blank Rune — the base item used to open the portal into the Prisoners' Quarters.
Barrier Rune — interacts with barriers blocking certain passages.
Spawner Rune — tied to mob spawner mechanics in the dimension.
Concierge Respawn Rune and 
Conjunctivius Respawn Rune — obtained after defeating each boss; they let you re-summon those bosses.
Obelisks and Elites
Concierge Spawn Obelisk and Conjunctivius Spawn Obelisk are the boss-summoning structures. Elite Obelisks are separate: activating one upgrades nearby mobs into ELITE versions with more health and better drops. Only trigger an Elite Obelisk when you have room to fight and Cells already banked.
Setting Up Respawns
After earning a boss Respawn Rune, place it near the corresponding arena so you can re-challenge the boss without a full run. Combine this with the 
Cell Holder — bank Cells, refight the boss, bank again. This loop is the fastest way to farm boss-exclusive drops like Boss Stem Cells and Conjunctivius's Tentacle.