How did she add that smoke effect?

Question

https://code.sololearn.com/WAP6C8D26jD4/?ref=app

Answer 1

2 circles using opacity when the 2 circles merge they become less transparent 👍
https://code.sololearn.com/W52DhfLiYFLF/?ref=app

Answer 2

Code master 😉👍 welcome

Answer 3

D_Stark Thanks!!!!!