[GAMEPLAY] Creep block from Illaoi vessel (E) fog

If Illaoi casts their E on you and you run away, the green fog that appears after you've run past the range of the vessel seems to give you creep block. I've only had it happen once - I don't own Illaoi so I can't try and replicate it. When it happened I was spam clicking away (but in the same location, a long distance from my character). I'm not sure if this would have had a different effect if I had just clicked to move once? It was like I was walking through a maze, my character seemed to be picking its way through between the green lines on the ground.

As I don't own the champ and can't replicate it, I'm not sure if it's 100% of the time, but:

1. Have Illaoi cast E on you
2. Move outside of the vessel radius so that the green fog and tentacles start appearing.
3. The green fog gives creep block when you try and move.

Thanks.