Mega Starmie is likely inspired by the 1956 film Warning from Space, which features starfish-like aliens called Pairan.
Alongside its Psychic typing, Starmie's possible alien origins have been hinted at in Pokedex entries for decades:
When away from human eyes, its core is said to glow mysteriously in seven colors. This Pokémon may have come from outer space.
- Pokemon Stadium
It is said that it uses the seven-colored core of its body to send electric waves into outer space.
- Pokemon Crystal
This POKéMON has a geometric body. Because of its body, the locals suspect that it is an alien creature.
- Pokemon FireRed (also present in the Japanese version of Red)
At the center of its body is a red core, which sends mysterious radio signals into the night sky.
- D/P/Pl/B/W/Y/BD/SP/Z-A
Its unusual body shape, reminiscent of abstract art, led local people to spread rumors that this Pokémon may be an invader from outer space.
- Pokemon Moon
Based on some of the stances and poses that Mega Starmie makes in battle, it may also be inspired by Ultraman. It could also be inspired by the Starmen from EarthBound—one interesting note is that Creatures Inc. is a successor to Ape Inc., the studio involved with EarthBound.
Overall, Mega Starmie seems to draw a lot of inspiration from the tokusatsu Japanese film genre, which often depicted superhero or sci-fi themes involving fantastical creatures. So this design is probably targeted towards fans of certain media franchises that are popular in Japan, who might find it nostalgic, though the references tend to not be relatable to Western audiences.
