Effect: A sphere of light explodes periodically, instantly killing all non-boss enemies in range. Bosses take 4% Max HP instead. Each copy reduces cooldown by 3s and increases radius by 10.
Unlock: Kill Big Bob on Graveyard using lamp damage as the killing blow
Bob's Light is an Epic item that triggers a periodic light explosion centred on your position. Every non-boss enemy inside the radius is instantly killed - no damage scaling, no damage multiplier required, just an immediate death. This makes it one of the few items in the game whose clear potential is entirely independent of your damage build. The explosion fires roughly 2 seconds after you pick up the item, then repeats on the current cooldown cycle.
Bosses are not killed by the effect. Instead, bosses take 4% of their Max HP as damage per explosion. Red ghosts (the Final Swarm overtime enemies) have a 33% chance to be instantly killed by each pulse. If the kill chance does not trigger, they take 4% Max HP damage instead.
The in-game description says the cooldown starts at 45 seconds and reduces by 3 seconds per copy. That is technically accurate, but the first copy also receives the 3-second reduction - so one copy fires every 42 seconds, not 45. This is confirmed by megabonkinfo.org's datamined formula: Cooldown(n) = max(5, 45 - 3n). At n=1, that gives 42s. The minimum cooldown of 5 seconds is reached at 14 copies.
| Copies | Cooldown | Radius | Notes |
|---|---|---|---|
| 1 | 42s | 60 | First copy, fires ~2s after pickup |
| 3 | 36s | 80 | Noticeably more frequent |
| 5 | 30s | 100 | Twice per minute |
| 10 | 15s | 150 | Four times per minute |
| 14 | 5s (min) | 190 | Maximum frequency |
| 20 | 5s (min) | 250 (max) | Both caps reached |
The radius scales only with additional copies of Bob's Light - not with the Size stat or Size Tome investment. This is confirmed explicitly by megabonkinfo.org. Investing in Size Tome expecting to expand the explosion area will have no effect on Bob's Light.
Kill Big Bob on the Graveyard map using lamp damage as the killing blow. Big Bob is the stage boss of the Graveyard, accessed by collecting four Crypt Keys from Crypt Ghosts and returning to the boss arena. The boss arena contains four lamp posts that you charge by standing near them. These lamps deal damage to Big Bob and also protect you from his one-shot darkness attack - you must be inside an active lamp's light when he casts it or you die instantly. The unlock requires that lamp damage deals the final blow that kills him, not your weapons.
The old requirement was to deal all damage with lamps only - that was changed in a patch. The current requirement is just that lamp damage is the killing blow. You can use your weapons freely during most of the fight. Near the end, stop attacking and let the lamp damage tick Big Bob down to zero. Charge all four lamps before his one-shot darkness attack and stay inside one throughout. Having some extra jumps from Charge Shrines makes it much easier to navigate the lava floor sections during the fight.
Megachad - Megachad's AFK Aura playstyle is the natural home for Bob's Light. He stands still, Aura deals continuous damage, and Bob's Light periodically wipes everything in the surrounding area that Aura hasn't already killed. Multiple Megachad AFK build guides list Bob's Light alongside Campfire and Idle Juice as core stationary sustain and clear items. The pulse is entirely passive - no input needed, no movement required - which fits perfectly into a build that is already designed to play itself. Megachad's Muscle Flex invulnerability also ensures he survives to the next explosion even in heavy swarm phases.
Roberto - Roberto unlocks by defeating Big Bob (the same boss that unlocks Bob's Light), making the two progression milestones naturally linked. Roberto's Hoarder passive spawns a free chest every 60 seconds, which significantly increases the chance of finding and stacking multiple copies of Bob's Light within a run. More copies mean faster cooldowns and larger radius. The megabonk.org Roberto guide notes that Overpowered Lamp is a late-game priority item for Roberto - while Overpowered Lamp does not interact with Bob's Light directly, Roberto's item-stacking playstyle extends naturally to accumulating copies of Bob's Light for the cooldown reduction.
Ogre - Ogre's passive grants +1.5% Damage per level and his playstyle revolves around holding ground with high HP and AoE coverage. He tends to stay in a fixed position as enemies converge, which means Bob's Light's centred explosion consistently catches the enemies clustering around him. Ogre runs typically stack Max HP investment, which also makes boss encounters more survivable - and the Graveyard's Big Bob fight specifically rewards surviving the darkness attack by standing in lamps, which benefits from having the HP buffer to take incidental damage during the fight to unlock Bob's Light in the first place.
Bob's Light periodically triggers a light explosion centred on your position. Non-boss enemies inside the radius are instantly killed. Bosses take 4% of their Max HP as damage. Red ghosts have a 33% chance to be instantly killed, otherwise take 4% Max HP damage. One copy fires every 42 seconds with a radius of 60. Each additional copy reduces cooldown by 3s (minimum 5s at 14 copies) and increases radius by 10 (maximum 250). Size Tome does not affect the radius.
Kill Big Bob on the Graveyard map using lamp damage as the final blow. Big Bob is the Graveyard stage boss - reach him by collecting four Crypt Keys from Crypt Ghosts. In the boss arena, charge the four lamp posts to deal damage and stay inside them during his one-shot darkness attack. Deal most of the fight damage with your weapons, then let lamp damage tick down the last of his HP for the killing blow. After unlocking, purchase Bob's Light from the Unlocks shop with Silver.
Big Bob is the stage boss of the Graveyard map, Megabonk's third biome added in the Spooky Update (v1.0.41). He inhabits a dark stone boss arena with four lamp posts. He has a one-shot darkness attack that instantly kills you unless you are standing inside one of the four charged lamps. Defeating him with lamp damage as the killing blow unlocks Bob's Light. He also drops a reward toward the Roberto character unlock chain.
Not for instant kills. Bob's Light cannot kill bosses outright - it deals 4% of their Max HP as damage instead. Red ghosts in the Final Swarm have a 33% chance to be instantly killed per explosion; if the chance doesn't trigger, they also take 4% Max HP damage.
They are entirely separate items. Bob's Light creates periodic light explosions that instantly kill nearby non-boss enemies - it has no brackets and does not scale with your damage stats. Bob (Dead) summons a ghost every 14 units you move that damages nearby enemies - it scales with player level and Damage Multiplier. They share a name theme but have completely different mechanics, unlock requirements, and optimal builds.
