Remove Contact Slowdown when Weightless or in the Air

Content.Shared/Movement/Components/AffectAirborneMovementComponent.cs

@@ -0,0 +1,11 @@
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Movement.Components;
+
+/// <summary>
+/// On entities that apply contact speed modifiers to airborne entities, e.g. flying mobs.
+/// </summary>
+[RegisterComponent, NetworkedComponent]
+public sealed partial class AffectAirborneMovementComponent : Component
+{
+}

Content.Shared/Movement/Systems/SpeedModifierContactsSystem.cs

@@ -1,6 +1,7 @@
 using Content.Shared.Inventory;
 using Content.Shared.Movement.Components;
 using Content.Shared.Movement.Events;
+using Content.Shared.Gravity;
 using Content.Shared.Slippery;
 using Content.Shared.Whitelist;
 using Robust.Shared.Physics.Components;
@@ -12,6 +13,7 @@ namespace Content.Shared.Movement.Systems;
 public sealed class SpeedModifierContactsSystem : EntitySystem
 {
     [Dependency] private readonly SharedPhysicsSystem _physics = default!;
+    [Dependency] private readonly SharedGravitySystem _gravity = default!;
     [Dependency] private readonly MovementSpeedModifierSystem _speedModifierSystem = default!;
     [Dependency] private readonly EntityWhitelistSystem _whitelistSystem = default!;
 
@@ -95,6 +97,11 @@ private void MovementSpeedCheck(EntityUid uid, SpeedModifiedByContactComponent c
                 if (_whitelistSystem.IsWhitelistPass(slowContactsComponent.IgnoreWhitelist, uid))
                     continue;
 
+                // entities that are weightless or in the air, i.e. no gravity or flying mobs, should not be affected by contact speed modifiers
+                // unless the entity applying the contact speed modifier has AffectAirborneMovementComponent
+                if (!HasComp<AffectAirborneMovementComponent>(ent) && (_gravity.IsWeightless(uid) || physicsComponent.BodyStatus == BodyStatus.InAir))
+                    continue;
+
                 walkSpeed += slowContactsComponent.WalkSpeedModifier;
                 sprintSpeed += slowContactsComponent.SprintSpeedModifier;
                 speedModified = true;

Resources/Prototypes/Entities/Objects/Misc/kudzu.yml

@@ -10,6 +10,7 @@
     - type: Transform
       anchored: true
     - type: Physics
+    - type: AffectAirborneMovement
     - type: Kudzu
     - type: GrowingKudzu
     - type: ActiveEdgeSpreader