as an action, you summon a wall at a point that you can see, any creatures in the way of the wall will be pushed back 5 feet, said wall is 5 feet by 20 feet and is 10 feet tall, said wall has an ac of 15 and an hp of 30,  alternatively, you can summon 1d4 landmines at any points in line of sight, said landmines are invisible, if they are stepped on or hit with an attack, the creature must make a con/dex save with a dc of (8+ your int modifier) to avoid taking 2d6 force damage and 1d4 fire damage

note from the dm: for the love of god remember where you put your landmines!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!