Weird Situation

What'll happen, can anyone guess? Star Eater targets Gran Mole, Star is unaffected by cards when it attacks, but it doesn't say I can't activate, meaning I could activate and return Gran Mole only. Or maybe that's illegal because it says both targets. What you guys say to it?

Star Eater is mandatory effect, Grand Mole is trigger effect. Star Eater attacks Grand Mole, which triggers Grand Mole effect, Grand Mole target both monsters, but when it resolves, only Grand Mole goes back to hand.

But again I'm bad at rulings so not sure.

That's what I think as well, but when the ADM came he said even if I use Mole eff nothing happens because both monster must return for it to resolve. I'm not sure if it's the final truth but I'm putting it here for discussion XD

I believe grand mole requires both monsters to be returned in order to be fully activated.

Actually, it resolve by returning both monsters to hand, means grand mole won't be able to return to hand, neither the opponent's obviously.

I guess it's finally solved then, nothing'll happen.

View below link to pojo question:

http://www.pojo.biz/board/showthread.php?t=1028843

In Vennominaga vs Grand Mole, Grand Mole returns to the hand although Vennominaga remains on the field since it is unaffected by card effects. Same issue applies in this case. Grand Mole will be returned to the hand and Star Eater will remain on the field.

The plot thickens! Then, if what this forum say is the absolute truth I would have won that duel easily.