To create a shake or jitter effect in Spine, you can use a combination of existing features to achieve a similar result. While Spine does not have a native shake or wiggle modifier like After Effects, you can manually create this effect by adjusting keyframes and using the Graph view for more control over the motion.

Here are some tips to create a shake effect:

1. Manual Keyframe Adjustment: You can manually adjust the position of the bone or slot you want to shake. Create keyframes at short intervals with slight random variations in position. This can be tedious but gives you full control over the shake effect.

2. Graph View: Use the Graph view to fine-tune the motion curves. You can create a more organic shake by adjusting the curves to have sharp peaks and valleys, simulating a jittery motion.

3. Adjust and Offset: Utilize the Adjust and Offset buttons in the Dopesheet to quickly add variations to your keyframes. This can help in creating a more randomized shake effect without manually adjusting each keyframe.

4. Physics Constraints: In Spine 4.2, physics constraints can be used to create more dynamic and natural secondary motions. While not specifically for shaking, they can add a layer of realism to your animations.

5. Store Function: The Store function in the Graph view allows you to save and experiment with different variations of your animation. You can create a base shake effect, store it, and then make adjustments to see which version works best.

For more detailed guidance, you can refer to the following resources:

• Graph view
• Dopesheet - Adjust
• Physics constraints in Spine 4.2

Additionally, you might find this video on the Wave principle helpful for understanding how to create more organic motion: Wave principle video.

PeterBacall you can also easily achieve this effect using the adjust button as explained in this tip:
https://esotericsoftware.com/spine-tips#20-float