The magic of the spider is one that is confusing in how it even exists.
The Arachnid's Domain is an upgrader only obtainable from the Maniacal Pumpkin Pack. It has an insane multiplier of x275, and is usable twice with a total multiplier of x75625. This is a very good upgrader for late game, because it has a hefty power consumption of 100TU, making it unusable until late game normal mode.
This is based off the Corrupted Alchemy item, The Witch's Cove, despite being wider than it.
| Maniacal Pumpkin Pack | ||
|---|---|---|
| Main Item | Upgrader |  Arachnid's Domain •  Macabre Totem •  Pumpkin Tribe Upgrader
|
| Dropper |  Pumpkin Encapsulator •  Trippo Nacho Corrupto •  Ghost Town
| |
| Misc. |  Evilfull Golden Gate •  Pumpkin Cell •  Hallow's Eve •  Consecrated Sampler
| |
| Bonus Item | Addition 1 |  Giant Pumpkin •  Ghastly Instant Repeater •  R-O-B-O SPOOK 154 •  Squash Deployer
|
| Addition 2 |  Ghastly Conveyor •  Galactic Nova Pack
| |
| Marble |  The Gateway (currently unobtainable)
| |