Memory Alpha wrote:
Also never credited, the idea behind this episode [The Changeling] was inspired by the last episode of the original The Outer Limits. That episode, called "The Probe" (with Janos Prohaska, in a Horta-like rubber suit, and Mark Richman), featured an alien automated probe which headed for Earth after apparently encountering one of our deep space exploration devices. As in the Trek episode, the probe nearly kills everyone because of its imperative to sterilize.
Aside from that loose general idea, Star Trek
's "The Changeling" has nothing in common with the Outer Limits
episode "The Probe." In the OL episode, survivors of a plane crash at sea find themselves inside
a gigantic automated alien probe.
And if Janos Prohaska's creature suit seems "Horta-like," that's because it was later re-used, with modifications, as the Horta in "The Devil in the Dark".