I only know this works in Paradise - Meltdown Mode.
To replicate - play Kelvin with lane A to your right. With Kelvins Ult - Ice Wall, you can place it in a choke point which will initially block the minion wave. However, once the wall disappears, the minions still wont move. Later waves will still spawn and in turn get caught up on the first wave. Once their waves are stuck - they will not move again until someone on the opposite team kills the stuck minions. I have also noticed that sometimes when I test this both teams minions stop spawning in that lane for the remainder of that match. This URL is an image of the placement for Kelvins ult. Sorry for the low quality, but you can get the idea. It’s placed in the choke point beside the back turret. I believe the terrain slopes down at that point as well. https://i.imgur.com/939GBxe.jpg