This item belongs to the Spider Baby set. Collecting three items from this set will transform Isaac into a humanoid spider.
For the sake of simplicity, all damage values shown are multiplied by 10 and rounded up to the nearest number.
Damage values are no longer multiplied or rounded.
All stats effect damage dealt by Spider Mod is based on Isaac's damage stat.
Spider Mod reveals Mega Satan's health bar and is the only way to see his health.
In Repentance, doesn't reveal Mega Satan's life bar during his second phase anymore.
Spider Mod also reveals the health bar for Mother, the Ultra Harbingers, and The Beast. (Note: The Health Bar for The Beast might be in the lava, making Spider Mod's health reveal effect for that portion of the fight useless.)(Needs Confirmation)
Spider Mod shows the health of invincible enemies, holes created by Little Horn, and the golden statue of Ultra Greed.
Spider Mod doesn't show if a segmented enemy has individual segment health like Larry Jr. or a health pool like Chub. Against enemies with invulnerable segments such as Carrion Queen and Scolex, its indicators will not differentiate between damage dealt to invulnerable and vulnerable segments.
Spider Mod's damage doesn't account for enemy damage reduction or invulnerability, which means that the damage indicators for Mushrooms, Stone Grimaces, and similar enemies will be inaccurate.
If Isaac transforms into Spider Baby, it spawns a spider familiar who works similarly to Spider Mod.
BFFS!: Makes Spider Mod bigger and increases the chance for Spider Mod to spawn a battery or blue spider. No effect on stat effect damage.
Hive Mind: Makes Spider Mod bigger. Whether or not this impacts spawn chances or damage is unknown.
This item is a reference to Spidermod, a modification to the original Binding of Isaac, which was made by one of the lead Rebirth developers, Spider853. One feature of Spidermod was to show damage numbers onscreen.