Detention X (The Grim Adventures of Billy & Mandy)

"Detention X" is the second half of the seventh episode in the sixth season of The Grim Adventures of Billy & Mandy.

Plot
When Billy accidentally food-poisons Miss Butterbean, Principal Goodvibes offers Grim the job as substitute teacher, which Grim accepts as now Billy and Mandy have to obey him. Grim sends misbehaving students to the "Detention Dimension", a place of eternal classroom punishment, until only Mandy remains in his class.

Why It Deserves Detention

 * 1) Billy was very unlikable at the start here, as he poisoned Miss Butterbean by giving her a dirty, rotten apple for Teacher Appreciation Day. Though it was Miss Butterbean's fault too, as she could have just washed and cleaned the apple to fix the problem.
 * 2) * As always, his screaming can get on your last nerve.
 * 3) Few bits of gross-out humor here, such as Billy having a hamster up his nose, him picking a booger from his nose and Grim and Billy's underwear both being shown respectively.
 * 4) Plot Holes:
 * 5) * Why would you even hire a skeleton as a substitute teacher, anyway? Also, how was Principal Goodvibes or the students not scared of the Grim Reaper considering that he's a real skeleton with a scythe?
 * 6) * How would drawing a diagram on a chalkboard get you sent to another dimension?
 * 7) The Detention Dimension teacher's design looks very ugly and hideous.
 * 8) Although everyone else did something bad to get sent to the Detention Dimension, Grim told Mandy to draw a diagram on the chalkboard, but apparently, that lead Mandy to the Detention Dimension as well.
 * 9) Bad Ending: When Mandy gets sent back to the school, she beats up Grim. Then, she gets into the car and said "the usual" to her mother as her response about how school went. It then ends with Grim getting punished with the same punishment Billy got (See the "Redeeming Qualities" section).

Redeeming Qualities

 * 1) Billy got his comeuppance by getting sent to the Detention Dimension and getting punished there with clowns, loads of books, having him with only his underpants and spiders around his body.
 * 2) Grim is still a tolerable character, as always.
 * 3) When Billy was punished with clowns, He said "DESTROY US ALL!" Again!