So this is a pretty easy passive tame:

1. Place a single foundation

2. Place 3 walls and a double door on the foundation

3. Stack 2 more walls high on your tube

4. Place 3 walls on the very top to make a U (just one wall missing)

5. Grab Arthur with an argie

6. Fly argie through the U, the walls will make you drop Arthur right into the tube trap.

7. Find the right spot to stand outside the tube trap and feed rotten meat

8. Enjoy your demon acid spitter Arthur

Also these things have creepy eyes