Steal a Brainrot Summer Index Guide: All 20 Brainrots & Summer Base

The Summer Index is a limited-time collection challenge added to Steal a Brainrot on 13 June 2026. It tracks 20 exclusive summer-themed brainrots, and collecting 18 of them unlocks the coveted Summer Base skin for your base. This guide covers every confirmed entry, their verified income values, the Summer Fuse Machine mechanics, all available mutations, and the fastest route to claim your reward before the event closes.

What Is the Summer Index?

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The Summer Index is a special in-game tracker that records how many of the 20 summer brainrots you currently own. Progress is visible directly in the index UI, so you always know exactly how far you are from the 18-brainrot milestone that awards the Summer Base. The index is described as limited-time, meaning the window to complete it will eventually close — exactly when has not been officially confirmed, so it is worth prioritizing now rather than waiting.

Unlike permanent brainrot collections, the Summer Index runs on its own separate counter. Owning a summer brainrot at any rarity contributes exactly one count regardless of whether a mutation has been applied to it. This means there is no mechanical benefit to stacking copies of the same summer entry — your energy is better spent chasing the other tiers you are still missing.

The Summer Base is more than a cosmetic reward. Displaying a completed or near-completed Summer Index signals to other players that you have invested seriously in the event, which can influence trading negotiations and your standing on community leaderboards.

How to Get Summer Brainrots

Three new features were added alongside the Summer Index to give you ways to obtain these brainrots:

Summer Fuse Machine — The primary source. It sits in the middle of the map, next to the Shop. Load 4 of your own brainrots into it, press E to open the fuse menu and preview the potential result, then press Fuse. The machine averages the rarity of your four inputs to decide the output tier, with a small chance to step up one rarity tier above average. Processing time scales with rarity: roughly 15 minutes for Epic and below, 30 minutes for Brainrot God tier, and up to 90 minutes for a Secret-tier result. Understanding this is critical before you start feeding it valuable brainrots — four Legendary inputs target a Legendary-tier summer output, letting you work up the ladder systematically without chasing duplicates.

Octo Lucky Block — Added during the same summer update. These blocks can include summer brainrots among their prizes, making them a useful secondary source especially for the Common through Epic slots. Exact per-rarity odds are still being tracked by the community, but they are worth opening whenever you have them spare.

RNG Machine — Also updated as part of the summer patch. Early community reports suggest it can yield summer brainrots across multiple rarity tiers. Use it as a parallel source alongside the Fuse Machine while the event is live.

One critical mechanic to keep in mind: fused brainrots are not automatically delivered to your base. You receive the brainrot at the machine and must carry it back yourself, leaving it exposed to theft during transit. This applies to every rarity. For Brainrot God and Secret results — which take 30 to 90 minutes to produce — have a clear path home ready when the timer finishes, or wait for a low-traffic server moment before picking up.

All 20 Summer Brainrots: Full Index Checklist

Use this table as your completion tracker. Income figures are the verified in-game stats from the RBLXGUIDE database. Items marked — are confirmed as Brainrot God tier by the community but not yet fully data-mined.

Four summer brainrot slots remain unconfirmed by the community at the time of writing. The good news: you only need 18 to claim the Summer Base, so even if some entries stay obscure, the reward is still reachable with the 16 confirmed names above plus two of the four unknown slots.

Summer Brainrots Value Ranking

Not all Summer Index entries are equal. Here is how the 16 confirmed entries rank by income-per-second — which matters both for your base's passive earnings and for trading leverage:

S-Tier — Game-changing income:
- Dragon Aquanini — $375M/s (Secret)
- Coco and Mango — $33.5M/s (Secret)
- Capitano Gullini — $22M/s (Secret)

A-Tier — Strong mid-range:
- Ombrello Topolino — $6.5M/s (Secret)
- Bombardiro Vaccariro — $1M/s (Secret)
- Sundrilla Sundae — $180K/s (Brainrot God)

B-Tier — Solid index filler:
- Bucketoro — $18.2K/s (Mythic)
- Cocoteddy — $15K/s (Mythic)
- Pi Pi Watermelon — $1.3K/s (Legendary)
- Cocosini Mama — $1.2K/s (Legendary)

C-Tier — Low income, still required:
- Penguino Cocosino — $300/s (Epic)
- Ti Ti Ti Sahur — $225/s (Epic)
- Pipi Avocado — $70/s (Rare)
- Pipi Corni — $14/s (Common)

Dragon Aquanini stands in a category of its own. The community-reported pull rate of roughly 8% from the Fuse Machine at Secret-input tier makes it the hardest and most time-intensive entry — but at $375M per second it is also far and away the most valuable summer brainrot and one of the top earners in the entire game.

Mutations and Summer Brainrots

Mutations in Steal a Brainrot apply a cosmetic and stat modifier on top of any brainrot, including summer entries. The full list of available mutations — Phantom, Default, Yin Yang, Bloodrot, Radioactive, Neon, Diamond, Galaxy, Gold, Candy, Rainbow, Cursed, Divine, Lava, Cyber, and Disco — does not affect whether a brainrot counts toward the Summer Index. One summer brainrot equals one index point regardless of mutation tier.

That said, mutations matter significantly for trading. A Dragon Aquanini with a Rainbow, Divine, or Galaxy mutation is substantially more desirable in player-to-player trades than the same brainrot at Default. If you obtain duplicate high-rarity summer brainrots, check their mutations before trading — you may be sitting on something much more valuable than its base income suggests. For a complete list of every brainrot's stats and mutation options, visit the brainrots page.

Completion Strategy

You do not need all 20 to claim the Summer Base — 18 is the threshold. That means you can deliberately skip the two hardest or most time-consuming entries and still earn the reward. Here is the most efficient three-phase approach:

Phase 1 — Clear the lower tiers in a single session. Load Common through Legendary inputs into the Summer Fuse Machine to lock in Pipi Corni, Pipi Avocado, Ti Ti Ti Sahur, Penguino Cocosino, Cocosini Mama, and Pi Pi Watermelon. Each run takes 15 minutes or less, meaning you can chain multiple fuses back-to-back and check off six index slots in one sitting.

Phase 2 — Target Mythic and Brainrot God over multiple sessions. Once tiers 1–6 are confirmed, escalate your fuse inputs to hit Cocoteddy, Bucketoro, Sundrilla Sundae, Lemonita Splashita, and Flippo Marino. Each run in this range takes roughly 30 minutes. Start two or three fuse cycles in parallel, do other activities on the server, then return to collect. This keeps throughput high without idle waiting.

Phase 3 — Pursue Secret slots selectively. Each Secret-tier fuse attempt can take up to 90 minutes. Since you only need 18 total, you can skip the two most difficult Secret entries and still hit the milestone. Dragon Aquanini and Coco and Mango are statistically the hardest to pull — consider banking your index progress at 18 without them if time or input brainrots are running low. If you do push for them, overnight or between-session fusing is a practical strategy given the 90-minute timer.

Security during transit. Always escort high-rarity fused brainrots back to your base the moment the machine finishes. A stolen Brainrot God or Secret entry is a major setback when you are racing toward 18. Choose a server with few other players for high-rarity pick-ups and take the most direct route to your base.

Use all three sources in parallel. Do not rely solely on the Summer Fuse Machine. Octo Lucky Blocks and the RNG Machine can fill Summer Index slots independently and should run concurrently. For active codes that may accelerate your progress, check the Steal a Brainrot codes page.