Forum:Change of control, change of effect?

Here's another question from a friend and my duel the other day. I normal summoned Dwarf Star Planeter who's effect is when it's normal summoned, during the end phase I can add a level seven light or dark monster from my deck to my hand. I attacked my friend's Graydle Alligator which when it's destroyed by battle, he can equip it to a monster and take control of it so he took control of my Dwarf Star Planeter. His argument was that during the end phase, he got the effect of adding a level 7 monster to his hand and I argued that since I triggered the effect, I got the effect. Who's right here? Or are we both wrong?