Tale of Diep (ToD) is no longer under active development as a derivative of Diep.io and remains here as an archive, though spin-offs such as The Extended Tale of Diep remain active. For info on the successor to Tale of Diep, now an independent work called "A Tale Where Nothing Matters", visit its Discord server here.

Hello! Yes, this is Dr. Lacus speaking to you from over the intercom. I regret to inform you that you are now part of one of my BIGGEST PROJECTS YET! In my spare time I have been modifying and weaponizing various polygons my fellow researchers have been collecting from outside the lab. You still all have to kill each other though... so get on with it! BWA HEE HEE HA!


Polygon Playground is a variant of FFA available to any player at any time after they have successfully survived a run of Mad Science and have beaten the Polygon Mother in Boss Frenzy at least once. After these two prerequisites have been met, Polygon Playground can be entered at any time. Beating Polygon Playground for the first time unlocks Companions for the player.


  • Polygons fight back! Dr. Lacus has equipped them with various weapons! Leveling has never been harder!
    • Every Polygon spawned has a 10% chance of being a 'Prototype Polygon'. Each shape has three prototype versions.
    • This is completely inspired by the likes of Project Nest in regard to weaponized Polygons. Thank them.
  • Every 1000 of a Polygon-type killed, its boss will spawn... with its own modifications by Dr. Lacus.
    • These bosses are enmain titled the Mechagon Bosses, and their modifications are listed below.
    • All Mechagon Bosses have the same health as their regular forms.
  • In the center of the map is the 'Mecha-Pentagon Nest', a modified Pentagon Nest where the ground is replaced with the metallic texture used on most of the creations by Dr. Lacus. Every Pentagon and Alpha Pentagon here has 2x more health and give twice the XP, but have a thin metal layer around them like some of the Mechagon Bosses.
    • Prototype Crashers have a way higher chance of spawning here.
    • There is also a high chance that spawned Pentagons will be a Polyguard (one of the Prototype Pentagons), as they both share the metal layer outline.
    • Every time a Mechagon Boss spawns, it will be in the Mecha-Pentagon Nest.
    • As the game mode progresses, the metal tiles of the Mecha-Pentagon Nest will begin spreading, but never consuming more than a third of the map.
    • 'Teleportals' dot the Mecha-Pentagon Nest. Teleportals are rimmed with dark gray metal and have a glowing neon blue interior and a symbol with a beveled letter 'L' printed on the front of the rim. Every once in a while, a random assortment of up to ten of any Prototype Polygons will be spawned. Teleportals have no effects on players and cannot be destroyed.
      • A Teleportal will let you know it is spawning enemies by having the interior begin gradually flashing red faster over the course of eight seconds.
      • Teleportals cannot spawn a group of enemies within thirty seconds of the last.
      • As the Mecha-Pentagon Nest grows, more Teleportals will form.
      • Teleportals are quite far and few between. At the start of the game, there will only be one or two, but this number grows as the Mecha-Pentagon Nest spreads.
  • Once a player has seen the death of all four Mechagon Bosses, the Companions feature will be unlocked, and they will receive one of the four Companions obtainable from beating Polygon Playground. Each successive time beating the four Mechagon Bosses will give another Companion, up to four.
    • Companions unlocked from this game mode include: Baby Square, Turret Boy, Lil' Buddy, and Bomb Devil.

Mechagon Bosses

Guardian L

Summoner Mk. II

Defender Prime


Mechagon Bosses each have their own page which go a lot more in detail. This is just a summary.

  • Guardian L: Having drawn inspiration from the Cult's Guardian X, Dr. Lacus took his own Guardian and exposed it to the power of science. The Guardian L has thin gray armor on all sides, and a wider spawner. Has metal lines and plating on it like the War Machine. Spawns larger Crashers which will occasionally be a Prototype Crasher, including Crasher Dashers. When near death, runs away leaving behind a trail of Crashers. Phases in and out of Armored periodically.
  • Summoner Mk. II: To idealize the power of the quadrilateral square shape, Dr. Lacus invented an even more powerful Summoner. The Summoner Mk. II has small Auto Turrets positioned on each corner, and a laser pod akin to the War Machine's in the middle of it. This will fire lasers just like the War Machine. Summons more squares at a time, and will even bring in Prototype Squares, like Square Sprinklers and more.
  • Defender Prime: A modified Defender with a center Dominator cannon, it might just go to show the power of the already insurmountable enemy. Whichever direction the Dominator cannon faces will not only have bullets fired out, but also get a projected Protector shield about eight tiles out that rotates with it, reflecting back all bullets fired at it. Unlike regular holographic Protector shields, this one can not be broken under any circumstance save for the Defender Prime's death. Every time it loses 20% of its health, twenty random Prototype Triangle types will spawn from around it.
  • Penta-Powergon: An Alpha Pentagon with a vengeance since their massive kind have been tormented for so long. Dr. Lacus hooked it up with some special toys that should CERTAINLY make it indestructible. Phases in and out of Armored. Looks like an Alpha Pentagon with thin metal armor on all sides like a Polyguard. Has a Griever hook centered on top of it, and Dominator Auto Turrets on all other sides. On top of it is a metal-like pattern akin to the War Machine, marking the Dr. Lacus style on this one too. EVERY time the Penta-Powergon is damaged, there is a 5% chance for a Prototype Pentagon to spawn around it, or a 10% chance for a Prototype Crasher to spawn around it.


  • Draws inspiration from Project Nest and just in general things by Graviatar.
  • Dr. Lacus may edit the paragraph at the top over the intercom as he wishes, but the meaning and info must stay the same. Just the wording can change to be more in character.
  • The first four times you beat Polygon Playground, you will receive one of the four unlockable Companions that come from beating it in a random order. These Companions are Baby Square, Turret Boy, Bomb Devil, and Little Buddy.
  • Was originally not required to progress the story, but alongside Shadow of the Gladiator was soon made necessary to complete at least a couple of times before Tower of Gladii could be accessed.
  • Since the gamemode doesn't end but it is required to be beaten to unlock Companions and progress the story, 'beating' the game mode means seeing all four Mechagon Bosses killed at least once. Even once that happens, the unlocks will be received and the game mode can be continued, allowing someone to knock all content out of it at once with enough time.
  • The Mecha-Pentagon Nest was an added feature because of text added on the Penta-Powergon page.
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