When the investment arm of Amazon's Alexa division led a $5.6 million investment in his startup, Nucleus founder and CEO Jonathan Frankel was ecstatic.

Just a year later, he's furious instead.

On Tuesday, Amazon announced its latest voice-controlled device — the Echo Show — which does all the things that other Alexa gadgets do, plus a few important new capabilities. Namely, the gadget can serve as a home intercom system and video-conferencing tool like FaceTime or Skype, because it comes with the combination of a touchscreen and video camera.

That's bad news for Frankel, since the Nucleus product is basically the same thing: An Alexa-powered tablet computer designed to be a dead-simple home intercom system and video conferencing tool, too.

But to make matters worse, Amazon's launch video focused a ton on the communication features at the core of Nucleus' vision, rather than the e-commerce, smart-home or entertainment capabilities that the Echo Show also possesses.

"The degree to which communication is a core functionality of the device is pretty astonishing," Frankel said in an interview with Recode on Tuesday afternoon. "Their thesis is what our thesis was: Communication is that Trojan horse to get those devices throughout the home and throughout the extended family's home."

"The difference is," he added, "they want to sell more detergent; we actually want to help families communicate easier."

Frankel knew this outcome was a possibility, since an Echo with a screen had been rumored for some time; Recode reported in March that intercom and voice-calling features were coming, too. But he's still surprised by the brazenness with which Amazon has gone after one of its own portfolio companies.