This i agreeLOL That's also the Oodama but the larger version i.e Cho oodama
The version we're talking about translates into ''Big ball Rasengan'' ,the one which you're talking about is the ''Giant ball rasengan''
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It also tells that Minato's normal rasengan is the same size i.e Its basically the Oodama he uses but he hasn't named it like Naruto.It just shows that Minato is awesome..