Characters
Hey, it's a thingie! A fiendish thingie!
— George ‧ Help!

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker excitedly spots an unidentified gadget and can only call it a 'thingie', then upgrades it to a 'fiendish' one. The vague word and mock-menacing adjective make the line sound playful, half alarmed and half delighted.
Context reviewed