Question 2D change size transform.localScale cause rotation in 3d

We have:
- png of Player dragged to scene with rigidbody2d dynamic and collider2d.
- png of Egg dragged to scene with rigidbody2d dynamic and collider2d trigger. Tagged in inspector.

Object Player has size changing script (when player collide with tagged object - player grows, object destroys):

Code (CSharp):

1. using UnityEngine;
2.  
3. public class FeedChangeSize : MonoBehaviour
4. {
5.     public float grow;
6.     public float shrink;
7.  
8.  
9.     private void OnTriggerEnter2D(Collider2D collision) {
10.         if (collision.gameObject.tag == "canCola")//
11.         {
12.             transform.localScale += new Vector3(grow, grow,0);
13.             GetComponent<Rigidbody2D>().mass += 0.9f;//
14.             GetComponent<PlayerControls2D>().jumpForce += 0.5f;//
15.             Destroy(collision.gameObject);
16.  
17.         }
18.  
19.         if (collision.gameObject.tag == "Egg_crab_0")
20.         {
21.             transform.localScale += new Vector3(grow, grow,0);
22.             GetComponent<Rigidbody2D>().mass += 1.8f;
23.             GetComponent<PlayerControls2D>().jumpForce += 0.7f;
24.             Destroy(collision.gameObject);
25.         }
26.     }
27. }

Problem- Player rotate a bit around Y axis in 3D (remember its a 2D game, z rotation is locked) after every collision with tagged object.
Video of rotation https://vk.com/video49473556_456239420

 

Lock any Rigidbody2D rotations that you don't want to change, otherwise the physics system will spin things if it finds a net torque applied to them from a collision.

Also, I'm not sure changing the scale like that will reliably trigger collisions. You may need to call .MovePosition() with a zero vector to notify the physics system.

This is because with Physics (or Physics2D), never move colliders by the transform directly. You are bypassing the physics system.

Always use the .MovePosition() and .MoveRotation() methods on the Rigidbody (or Rigidbody2D) to move things.

 

Yes, you are right. In my Controls script Scale sets to -X to turn picture of player when it goes left and in Grow script grow var is +, so when player goes left we get -X+grow.