Can the idea be taken from a popular show or series?
Dont think so, can be flagged for copyright
As long as it doesn’t look completely identical
Synthwave Helmet for example is a Daft Punk reference
Claymore is also a reference weapon
Say you want to make a Final Fantasy 7 reference and create Sephiroth’s One-Wing.
It could look somewhat similar as long as it doesn’t copy the design. Then again I doubt they’ll be adding such a wide sprite.