blending between meshes

Im working on the death animation for my enemys, and I want to have them melt into a puddle, how would I transition their mesh into a sphere?

Current Code :

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class enemyManipulation : MonoBehaviour {
	public int Health = 100;
	public Slider Slider;
	// Use this for initialization
	void Start () {

	}
	
	// Update is called once per frame
	void Update () {
		Slider.value = Health;
		if(Health <= 0) {
			//Transition Mesh
		}
	}
}

Short answer: You can’t. Use an effect to cover up the transition.

Long answer: You’d have to build the mesh specifically to be morphed this way, and find a way to animate it as such. This would be incredibly difficult even for a skilled technical artist. Note that even in AAA games, they almost never do straight morphs, and usually cover it up with obscuring geometry or particle effects.