It’s far from realistic, and far from using dynamics of any kind. If you need to create a splatter effect of any kind, Trapcode Particular can do it pretty easily. Tutorial creator Voxyde shows how you can use a really basic Particular simulation to create a liquid-like spatter effect.
The trick comes in stacking After Effects layers and effects to mesh the particles together to create a more fluid look. The 3D look comes from After Effects’ own Glass effect, and roughen edges is used to get a more random blobby shape to the particles.
Even though Trapcode Particular shows its age as a particle system it is still quite handy for little tasks like this. Keep in mind the gap is closing with more modern takes on particle systems like Stardust for After Effects. If you are a Hitfilm user, that software comes with a blood spatter effect right out of the box.