A simple scene were a person transforms into venom by using geometry nodes. Here is the final:

Here are the steps I used to make it:

1. The person transforms and sizes up at the same time.

2. The person transforms and then sizes up.

3. I hid the person to see the global effect.

4. The person is still hidden. I then decided to make the person not to size up.

5. To see the result I revealed the person.

6. I then added clothes to make the scene more realistic.

7. I added a tongue to the person and made the eyes white to make a more human like person.

8. There, I added some tentacles to make Venom more... Venom.

9. Finally, I added a background to the scene and there we go!