Porta Prison

Speak to Trashmouth: First things first, you'll need to find Trashmouth. He's hanging out in Lectra City. Head over to the toilet located in The Underpass – that's where you'll pick up this side mission.

Kill Traitors / Collect Spray Paint: After chatting with Trashmouth, you'll need to make your way to a waypoint. Head underground where you'll encounter some enemies – these are the 'traitors' Trashmouth wants dealt with. Take them out, and then grab the Spray Paint they drop.

Spray Graffiti: With the Spray Paint in hand, head back to Trashmouth. You'll see a truck near the toilet; use it to get up onto the roof. Once you're up there, it's time to get artistic! Vandalize the walls by using the Spray Paint six times.

Destroy Dirty Cop Bot / Collect AI Chip: As soon as you're done with your graffiti session, a Sheriff Bot will emerge from the Police Station. Take this bot down, and then collect the AI Chip it drops.

Install AI Chip / Destroy Septic Tank: Now, take that AI Chip you just picked up and install it into the back of the toilet. After that, a bunch of Sheriff Bots will show up near the Police Station. Deal with them, and then focus on the Septic Tank located on the side of the toilet – destroy it.

Destroy Recycler Bot: Once the Septic Tank is gone, a Recycler Bot will come out of a room to your right. Hang back for just a few seconds, then take it out. You'll need to collect its AI Chip and install it into the back of the toilet, just like the last one.

Find Trashmouth: Finally, Trashmouth decides to make a run for it. You'll need to teleport to Meridian Outskirts. Hop into a vehicle and head towards the waypoint. Your objective here is to take out Trashmouth's Technical before it escapes. Once you've dealt with it, pick up the Illegal Weapon it drops to complete the Porta Prison side mission.