To roll Lucky with 90% confidence in 8 hours AFK, the leanest free stack is Ultra Luck + Lucky + Huge Lucky, finishing in roughly ~6.1 hrs. Want it faster? Add potions or a gamepass; the table below ranks tradeoffs.
| Window | Stack (fastest path) | Time to 90% | Reachable? |
|---|---|---|---|
| 1 h | R2 + Ultra Luck + 2× Gamepass + Lucky + Huge Lucky | ~55 min | Yes |
| 4 h | Ultra Luck + 2× Gamepass + Lucky + Huge Lucky | ~3.1 hrs | Yes |
| 8 h | Ultra Luck + Lucky + Huge Lucky | ~6.1 hrs | Yes |
| 24 h | Lucky + Huge Lucky | ~18.3 hrs | Yes |
Lucky has a base drop rate of 1 in 21.5K per roll. To reach 90% confidence of pulling at least one within an 8-hour AFK window, you need to land at effective odds where the geometric distribution `1 - (1 - p)^n` clears 0.9 over the available roll count.
The plan above uses a luck multiplier of roughly ×6429.8, pulling effective odds to 1 in 3. Across 7.5 rolls/min for 8 hours, that clears 90%.
The other two rankings (cheapest, simplest) trade time for resource savings. If you’re grinding overnight, the cheapest plan often beats the fastest one because the extra hours cost nothing.
Lucky Slime deserves a retained stack page because it changes every later hunt, not just one combat slot. The passive turns future rolls into cheaper attempts, so the stack decision has compounding value.
Lucky Slime fits the first serious mythic chase, after a player can keep rolling through potion windows but before Huge targets are realistic. It is the bridge between casual rolling and planned farming.
Lucky Slime stack math depends on documented drop odds plus the Lucky passive value used across the calculator. Treat roll-speed timing as community-reported guidance rather than primary in-game telemetry.
Lucky Slime differs from Stump because Stump is mainly a body to equip, while Lucky Slime improves the account math behind every target that follows. That makes the stack advice more durable.
The common mistake with Lucky Slime is waiting for a perfect high-rebirth stack before trying. A modest free stack can still be rational because an early pull improves all later sessions.
Cost columns are concrete. Time columns assume our reconciled defaults (Lucky Slime Passive ×3, potion duration 3 min, 5 rolls/min standard or 7.5 with Roll Speed Boost). These values are sourced from three independent community references but haven’t been primary-verified in-game. Treat as guidance, not gospel.