Amazon is launching Astro, its first household robot, powered by its Alexa smart home technology.
The company said it can be remote-controlled when not at home, to check on pets, people, or home security.
It can also patrol a home automatically and send owners a notification if it detects something unusual.
Amazon said it was more than "Alexa with wheels" and had been programmed with a range of movements and expressions to give it personality.
It demonstrated asking Astro to "beatbox" - and the robot bopped its head and made expressions while playing hip-hop beats.
Amazon was also keen to pre-empt privacy concerns.
It said Astro can be set with "out of bounds" zones, so it cannot go into certain areas, or could be set to "do not disturb". It also features buttons to turn off cameras and microphones - though it loses its ability to move around when they are switched off.
The small robot also comes equipped with an extendable "periscope" camera that pops up from its head. Amazon showed an example of using it to check if a gas hob had been left on after leaving the house.
The technology and retail giant suggested that the $999.99 (£740) robot could be a help to the elderly.
"Astro is a bold move by Amazon, but a logical step given its expertise in robots and desire to become more integrated into consumers' daily lives,"said Ben Wood, chief analyst at CCS Insight.
Unlike some rivals, Amazon "is willing to bring highly experimental products to market" and see how customers react, he said.
"Offering products resembling something from a science fiction novel positions Amazon as an innovative company in the eyes of consumers and investors," he said.
The robot will ship later this year, Amazon said - but only in the US. And after the initial, limited run, its price will go up to $1,449.99, it said.
"I believe the Astro robot will sell out in minutes when it becomes available in the US market," Mr Wood said. "I'm just gutted that it won't be shipping in the UK in the foreseeable future."
Amazon wants a slice of the robotics market, boldly stating that it believes all homes will have one in five to 10 years.
It wants Astro to be that must-have new member of the household, and there is no denying that the little wheeled robot is pretty cute - although the periscope that pops out of its head is a little creepy.
But we have seen other cute humanoid robots - such as Pepper - fail to make a mark.
This is largely because the price tag means it will be a toy for the rich for some time to come. And while Amazon was keen to convince us that for that you get more than "Alexa on wheels", it was hard to see a compelling use case for this other than to curb that ever-present paranoia that you left the oven on.
But building robots is hard. And if the home robotics market is ever going to take off, people will have to be convinced to spend a lot of money.
This first foray offers Amazon a chance to hone its skills. And arguably, there is no company already as firmly embedded in our homes as Amazon.
The company is known for occasionally making unusual smart home tech such as its Alexa-controlled microwave from 2018.
At last year's event, Amazon turned heads with a flying indoor alarm drone. The Always Home Cam launches from its deployment bay if it detects a potential intrusion, and can fly around a home to check with a video feed. But it was not launched and no more details were released in the past year.
Instead, Amazon on Tuesday said it was opening up the invite list for early adopters to buy the drone on a limited basis - but did not give dates for widespread availability.
Among the other devices unveiled at the event was the the Amazon Glow: a video calling device that has the ability to project an interactive "touchscreen" on the floor or table in front of it.
The idea is to engage children during long video calls, as they can play games or draw on the 19-inch projected "screen" while on the video call. Relatives on the other end can also interact with the projection through a tablet app.
In one example, Amazon said children could "scan" a favourite toy using the Glow's camera, and turn it into a jigsaw puzzle to reassemble.
Other new products announced included:
a Disney-themed Alexa version, featuring the voices of Disney characters, to be rolled out next year
updates to the Amazon Halo workout band, with a new model called Halo View.
a new model of Ring smart alarm with a built-in wifi router
a paid "virtual security guard" Ring subscription which allows a remote operator to check cameras triggered by motion detection
The event also coincided with the launch of Amazon's much-delayed video game New World, its second attempt at a big-budget title after the high-profile failure of its shooter Crucible last year.
Unlike Crucible, however, New World received some favourable feedback during a popular beta test in July which attracted hundreds of thousands of players.