The Grim Adventures of Billy and Mandy

Why would Irwin ask Mindy and why he doesn't have a reflection on the mirror when he already knows he's part vampire and he discovered about not having a reflection looking at a puddle of rain on the floor.

Baron Von Ghoulish the vampire from Billy and Mandy Save Christmas makes a quick cameo during the trick-or-treater eaters song.

When Mindy was brushing her hair, she was humming the trick-or-treater eaters song before she performed it.

Even though this is a spin off, the characters from the previous series have changed in design. Skarr has a moustache. Hoss Delgado has white sideburns and a chainsaw for a leg, (Irwin is changed but designed skeptical.) Jeff the Spider is lightly colored, and Fred Fredburger is shorter, less fat, and shaped more like a peanut.

Goof:

In Codename Kids Next Door, in Operation A.R.C.H.I.E.V.E, we learn that Sector V lives in Cleveland, Ohio. In The Grim Adventures of Billy and Mandy in Jeffy's Web, we learn that Endsville lives somewhere in New York, judging by the Statue of Liberty as seen in that episode. If they live in different states apart, then how come some characters from Cleveland showed up in New York? We see Tommy Gilligan, Numbuh 2's brother, in Endsville, and there was no explanation as to how he got there, whatsoever.

In Billy and Mandy's Big Boogey Adventure, Numbuh 3 promised to get back in Grim, but when Grim is captured, they don't even remember each other or the events of the TV movie. Reponse: To be fair, Numbuh 3 may have forgotten about it (she is somewhat ignorant) and Grim just didn't care.

The first five minutes of the movie, Ben 10: Race Against Time, were featured during the final commercial break.

Billy's butt was showen several times, and it didn't have a birthmark.

After El Uglio removes his mask, Mandy's costume disappears.

El Uglio calling Billy "hermano" is a reference to the Spanish language. In Spanish, "hermano" means brother.

While telling the story of El Dia de Los Muertos, the boy's hair turns black.

Nigel Planter's puppet is Pinocchio from Nursery Crimes and Billy Ocean.

Nigel Planter saying that he had movies and books is a reference to Harry Potter which Nigel is a spoof of.

In the Halloween special it mentioned that anything cut with grim's scythe will stay cut forever but in this episode billy cut grims head off and he put it back like nothing happened.

The real Dracula lived during the late 1300s in Romania. He can't be young in the 1970s.

Irwin is actually 1/4 vampire because his dad is 1/2 vampire since Irwin's Grandmama is a human and his grandpa is Dracula.

First time (via flashback) that we see Dracula as a younger man (during the late 1970's) and as a purple vampire bat.

It's revealed in this episode that Dracula is actually Irwin's Grandfather on Irwin's father's side; thusly making (as Mandy correctly identifies,) Irwin a half-vampire and half-mummy.

There was a scene that wasn't shown on TV where Mandy takes the knife from one of the guards, cuts the rope tying herself and Mindy, then Mandy holds the blade of the knife and throws it to the other guard's hair to the wall.