4. Gunion
Appearing only in the Muda Kingdom section of 1989's Super Mario Land, the Gunion are an aquatic, squid-like race of creatures. They have a relatively simple attack pattern, but are a bit of a nightmare to encounter thanks to the fact that upon their demise they launch two balls of what can only be described as "stuff", which home in on Mario wherever he may be on screen.
Pokemon Totally Ripped It Off With:
Tentacool
The Similarities
While Tentacool may not be ripping off Gunion
directly, I maintain that this article aims to draw attention the fact that Mario was doing wacky creature design way before it became Pokemon's main draw; that Mario arguably influenced the inception of the entire thing. The fact is, both enemies pictured above are anthropomorphic squid critters and both were included in their respective games as foes. In that respect, I reckon you can trace a line of influence back from Tentacool to Gunion, at least in terms of core design if not exactly in terms of finished product.
If Pokemon Had Got There First:
Potential Evolutions Squidgun
Gunion Octablast
Potential Moves Water Gun, Whirlpool, Bubblebeam, Wrap