If you have spent any time in Build a Base and Steal, you already know that events are the single biggest swing factor in your progression. They pop up every 30 minutes, and the right one at the right time can hand you a stack of mutations or a pile of cash you would otherwise grind for hours.
I have been running bases since the Build Mode Update dropped, and the events system is what separates casual players from the leaderboard chasers. This guide covers every Build a Base and Steal event, what each one does, how long it lasts, and which ones you should never miss.
Table of Contents
What Are All The Events in Build a Base and Steal
Build a Base and Steal currently runs six rotating events on a 30-minute cycle. Each event changes how money, pets, and luck work across the entire server for a short window.
The full Build a Base and Steal events list includes Money Rain, Roll Rush, Zombie Invasion, Cosmic Invasion, Volcano, and Fishing. Every event fires every 30 minutes and lasts between 4 and 10 minutes depending on the type.
All Events Quick Comparison
| Event | Effect | Duration | Best For |
|---|---|---|---|
| Money Rain | Money drops from the sky | 4 minutes | Fast cash farming |
| Roll Rush | Free pet and block rolls | 5 minutes | Rolling new pets |
| Zombie Invasion | x2 luck for rolls | 5 minutes | Luck grinding and stealing |
| Cosmic Invasion | Higher Cosmic mutation chance | 6 minutes | Cosmic pet farming |
| Volcano | Higher Inferno mutation chance | 8 minutes | Rare Inferno pets |
| Fishing | Catch fish pets from ponds | 10 minutes | Index completion |
Money Rain Event – Effects & Duration
Money Rain is the simplest event in Build a Base and Steal. Bills literally fall from the sky and you just walk around collecting them. Every player on the server gets the same drops, so the real trick is being online when it hits.
The event runs for 4 minutes, which feels short. In my testing, a clean run with a wide base layout nets around 15 to 20 percent extra cash on top of your normal MPS. That is a meaningful boost if you time it with a fresh base.
Pro tip: stand near the middle of your base rather than at the edges. Bills spawn in a centered radius and players at the perimeter tend to miss the densest cluster of drops before the timer runs out.
Roll Rush Event – Effects & Duration
Roll Rush is the event every pet hunter lives for. During Roll Rush, you get free pet rolls and free block rolls for 5 minutes straight. No cooldown, no cost.
I rolled three new pets in a single Roll Rush window during my last session. That would have taken me roughly two hours of normal grinding. If you have been sitting on saved-up roll tokens waiting for the right moment, this is it.
The catch is that the rolls still respect your base level. A Tier 1 base will mostly yield common pets even during Roll Rush. Save your serious rolling for after you have upgraded your base at least twice.
Zombie Invasion Event – Effects & Duration
Zombie Invasion is one of the most useful Build a Base and Steal events because it does two things at once. It grants a x2 luck multiplier on all rolls for 5 minutes, and it pulls half the server away from their bases to fight zombies in a shared arena.
The double effect is the entire point. While other players are distracted at the zombie arena, their bases are wide open. I have stolen three pets in a single Zombie Invasion window just by walking around unprotected bases.
Defending during Zombie Invasion means a strong wall setup with wall launchers. The zombies themselves are a mild threat compared to opportunistic thieves, so invest in four walls and at least two launchers before you start chasing luck rolls during this event.
Cosmic Invasion Event – Effects & Duration
Cosmic Invasion is a mutation-focused event that runs for 6 minutes. During the window, every pet you roll has a dramatically higher chance of becoming Cosmic, which is one of the strongest mutations in Build a Base and Steal.
Cosmic pets earn a permanent income multiplier that stacks with everything else. I rolled a single Cosmic pet during a Cosmic Invasion and it boosted my base income by about 18 percent for the rest of that session.
Stack Cosmic Invasion with Roll Rush if the timing aligns. Two Cosmic pets in one Roll Rush window during Cosmic Invasion is realistic, and that combo is what most leaderboard players chase.
Volcano Event – Effects & Duration
Volcano is one of the two rarest events in Build a Base and Steal. It runs for 8 minutes and increases your odds of rolling Inferno mutation pets, which are the rarest pet type in the game.
Inferno pets are tougher to roll than Cosmic. I went through three Volcano events before seeing a single Inferno, so do not get discouraged if your first window goes dry.
Private servers are the best place to grind Volcano. Without other players competing for rolls, every Inferno that drops is yours. Most players treat Volcano on a public server as a lottery ticket, but on a private server it becomes a focused farm session.
Fishing Event – Effects & Duration
Fishing is the other rare event, and it is the only one that does not affect your base directly. For 10 minutes, fish pets spawn in special ponds around the map. You use a fishing rod to catch them and add them to your index.
The fishing event is mostly about completing your pet index. Fish pets do not generate income the way standard pets do, but every unique fish you catch unlocks an index reward that includes bonus luck and cosmetic items.
Position yourself near a pond the moment the event starts. The first two minutes are the busiest because the ponds refill on a short timer. By minute seven, you will be waiting longer between catches, so early positioning matters more than grinding late.
Event Rarity Ranking & Priority Guide
Not all events are created equal. Based on my testing and what other top players report, here is the rough rarity tier list for Build a Base and Steal events from rarest to most common.
Tier 1 (rarest): Volcano and Fishing. Both events feel noticeably less frequent than the others and the rewards are gated behind heavy RNG.
Tier 2: Cosmic Invasion. Less rare than Volcano but still infrequent enough that stacking it with Roll Rush feels like a major win.
Tier 3: Zombie Invasion, Roll Rush, and Money Rain. These feel like they show up in roughly every other 30-minute cycle. They are reliable and worth planning your session around.
For solo farming, hop onto a private server before Tier 1 events. For stealing and chaos, public servers during Zombie Invasion are unmatched. For pure progression, never miss a Roll Rush on a server with low competition.
Build a Base and Steal Events FAQ
How long do events last in Build a Base and Steal?
Most Build a Base and Steal events last between 4 and 10 minutes. Money Rain is the shortest at 4 minutes, Roll Rush and Zombie Invasion run 5 minutes, Cosmic Invasion runs 6 minutes, Volcano runs 8 minutes, and Fishing runs 10 minutes. Events fire every 30 minutes on a rotating cycle.
Which event is the rarest in Build a Base and Steal?
Volcano and Fishing are the rarest Build a Base and Steal events. Volcano boosts your chances of rolling Inferno mutation pets, while Fishing spawns fish pets that unlock index rewards. Both feel noticeably less frequent than Money Rain, Roll Rush, Zombie Invasion, and Cosmic Invasion.
When does Money Rain happen in Build a Base and Steal?
Money Rain happens on the standard 30-minute event rotation. There is no fixed clock, so it fires at different times each cycle. The event itself lasts 4 minutes and drops cash across the entire server that any player can collect by walking through the rain area.
Can you farm events on a private server in Build a Base and Steal?
Yes, private servers are a great way to farm Build a Base and Steal events without competition. Private servers are especially useful during Volcano and Cosmic Invasion where every Inferno or Cosmic pet you roll goes directly to your base instead of competing with other players on the server.
Final Thoughts on Build a Base and Steal Events
The Build a Base and Steal events list covers six rotating activities on a 30-minute cycle, each with its own duration, effect, and best use case. Plan your sessions around Roll Rush for pets, Cosmic and Volcano events for mutations, and Zombie Invasion if you want to mix stealing with luck grinding.
Updated for 2026, this guide reflects the current Build Mode Update event lineup. Hop in, watch the timer, and stack your rolls during the right window. That is the fastest path to a top-tier base in Build a Base and Steal.