There’s a very specific feeling of safety that comes from building tall in Minecraft — get high enough off the ground, and most hostile mobs simply can’t reach you. Mob Spider Climb removes that safety net entirely. This mod gives any mob that uses standard ground-based navigation — the same AI system Zombies, Skeletons, and most other mobs rely on — the ability to climb vertical surfaces exactly like a Spider does. Suddenly, that watchtower or elevated base isn’t the safe zone it used to be.

It’s a small, focused change with a big impact on how defensible any structure actually is, and it’s built specifically to be combined with other mods that push mob behavior and world destruction further — turning survival base defense into something genuinely tense again.

What This Mod Actually Does

In vanilla Minecraft, wall-climbing is a Spider-exclusive trait, driven by a distinct piece of movement AI that lets it path directly up vertical surfaces. Mob Spider Climb takes that exact climbing behavior and makes it available to any mob using the default ground navigation AI — which, fortunately, covers the large majority of mobs in the game, both hostile and passive.

Once enabled for a given mob, that mob will path and climb using the same logic as a vanilla Spider. The mod’s author is upfront that this reused pathing AI can look a little “inelegant” at times — since it wasn’t originally designed for mobs like Zombies — but it gets the core job done: mobs that shouldn’t be able to reach you, suddenly can.

Which Mobs Can (and Can’t) Climb

Climbing behavior only works on mobs that natively use the default ground navigation AI. That includes most vanilla hostile and passive mobs, but a few categories are excluded by nature of how their movement works:

  • Flying mobs (like Phantoms) — unaffected, since they don’t use ground navigation to begin with.
  • Swimming mobs (like Guardians) — unaffected for the same reason.
  • Bouncing mobs (like Slimes) — unaffected, as their movement AI doesn’t route through the standard ground navigation system either.

Modded mobs can also be given climbing behavior, as long as they use the same ground navigation AI under the hood. If a modded mob doesn’t respond to the config, that’s the most likely reason why.

Full Configuration Guide

climbingMobsAllowList

This is the core setting: a list of mob IDs allowed to use climbing behavior. It works with any mob — hostile or passive — as long as that mob uses the default ground navigation AI.

  • Modded mobs are supported too, but must be entered using their full namespaced ID in the format modname:mobname — the same format used with the /summon command.
  • If your configuration keeps resetting back to default, it almost always means one of the entered mob names is invalid. Double-check spelling and confirm that the exact same modname:mobname string works with /summon.

climbingTag

This setting lets you gate climbing behavior behind a specific NBT tag instead of applying it to every instance of a mob. By default, it’s left as an empty string, meaning no tag is required and any listed mob can climb.

Setting this to a custom value — for example, canClimb — means only mobs carrying that exact tag will be able to climb, even if their mob type is in the allow list. This is especially useful for mapmakers who want climbing enemies to appear only in specific, intentional spawns rather than across every naturally spawned mob of that type. A tagged mob can be summoned like this:

/summon minecraft:zombie ~ ~ ~ {Tags: ["canClimb"]}

useAllowlistAsBanlist

This setting flips the entire logic of the mod. Instead of using climbingMobsAllowList to define which mobs can climb, enabling this option turns that same list into a banlist — climbing behavior is applied to every eligible mob in the game except the ones listed. This is the fastest way to make climbing a near-universal threat while still excluding a handful of specific mobs you don’t want affected.

Best Paired With

Mob Spider Climb is explicitly designed to combine well with other mods that increase environmental danger and mob capability:

  • Improved Mobs — adds mob block-breaking behavior, which pairs naturally with climbing mobs that can now also tear through your defenses to reach you.
  • Simple Block Physics — adds realistic block physics, compounding the chaos when climbing mobs and destructible structures meet.

Combined, these three mods push Minecraft’s base-defense gameplay toward something far closer to a genuine survival horror scenario — height and solid walls stop being reliable defenses on their own.

Frequently Asked Questions

Will every mob in my world start climbing walls by default?

No. Climbing behavior only applies to mobs you’ve added to climbingMobsAllowList (or excluded from it, if using banlist mode), and only if that mob uses the default ground navigation AI.

Can I make only some Zombies climb, not all of them?

Yes — use the climbingTag setting to require a specific NBT tag, then summon or spawn tagged Zombies specifically when you want climbing behavior to apply.

Why isn’t my modded mob climbing even though I added it to the config?

It’s almost certainly using a non-standard navigation AI (common for flying, swimming, or bouncing-style mobs). Only mobs using the default ground navigation system are supported.

Is the climbing movement smooth?

It reuses the vanilla Spider’s pathing AI directly, which wasn’t originally built for other mob body types, so movement can look a bit awkward at times. This is a known limitation the developer has noted may be improved in future updates.

What’s the difference between allowlist mode and banlist mode?

Allowlist mode (default) only gives climbing behavior to mobs you specifically list. Enabling useAllowlistAsBanlist reverses this, giving climbing behavior to every eligible mob except the ones you list.

That watchtower isn’t as safe as you think anymore. Configure Mob Spider Climb, pair it with a few destruction-focused mods, and find out just how far “up” you’d actually need to build.