Brain's disguises: mechanic
This is the first time that any of the Gadget family ever sees Mad Cat or a part of Dr. Claw.
Dr. Claw's voice changes at random times in this episode.
Gadget: (half way in the earth after a high fall, talking into the Gadget Phone) Is that you chief?
Chief Quimby: (muffled) I'm under you.
Gadget: (looking all around) You're where?
Gadget: Oh, my gosh! That car is on fire. I better use my Gadget-Snow-Gun to put it out! (Dr. Claw is coughing because of the smoke, while the Gadgetmobile puts itself right next to the MADmoblie)
Gadget: Don't worry, I'll save you! Go-Go Gadget-Snow-Gun! (Gadget fires his Snow-Gun, filling the MADmoblie with snow.)
Dr. Claw: (waving his hand menacingly over the window to Gadget, while MADCat grumbles about being covered in snow) It's full of dirty snow! I'll get you for this!
Gadget: Oh, he's waving thank you! Thanks are not needed my good man! Glad to be of service!
Gadget: (driving drunken; as he changes the Gadgetmobile to the Gadget Van back and forth) Hee-haw! Hee-haw! Hee-haw! Hee-haw! I'm a donkey!
The name of the racing competition Metropolis 500 is an allusion to the racing competition Indianapolis 500 which is annually held on Memorial Day at the Indianapolis Motor Speedway.