AI possessed a garage door, and it roars at kids until they say please

For Halloween, one garage door turned into a grumpy old pirate. The wooden boards split into a jagged mouth with fire glowing behind it, and the house grumbles at trick-or-treaters and tells them to go bother the neighbors.

An NVIDIA engineer built it for the kids who come trick-or-treating and wrote the project up on the company's Hugging Face blog. The backstory says the house was built from the timbers of a sunken pirate ship and is still annoyed about it. One word breaks the act: say "please" and it softens, say "thank you" and it waves you off almost kindly. Once you win it over, it remembers, so nobody has to negotiate with the same garage door twice.

Under the hood is a chain of NVIDIA open models. Nemotron ASR listens, the small Nemotron 3.5 Bolt E4B language model in its 4-bit version writes the replies, Magpie TTS Zeroshot voices them as a pirate from a short reference sample, and Audio2Face-3D moves the mouth in Unreal Engine 5. Nemotron 3 Nano Omni watches the camera and recognizes costumes, so the house can pick on the witch or the vampire personally. It has seven moods, from grumpy to delighted.

The personality comes from a LoRA trained on more than 5,000 conversations that another AI agent generated and judged while the author slept or worked the day job. Everything runs offline on one workstation with two RTX PRO cards. The median time from the end of a kid's sentence to the reply is 1.7 seconds, and cached jokes play in 0.72.

The MonsterHouse code itself isn't released, but every model it uses is available today, and the base, the open Nemotron Voice Agent blueprint, is on GitHub. The post includes a step-by-step recipe for building your own talking character: voice pipeline, brain, personality, voice, face and, optionally, eyes.

Bottom line: the meanest house on the block is built from free models, and you can copy it in time for next Halloween.