Yeah, what's happening is that you likely already destroyed the lobotomizer, but you got desynched and on your opponent's end you never did that.
So when he uses it to lobotomize your creatures, the game magically pops up another on his end, but you can't do anything about it anymore.
It can get really nasty if desynch occurs with devour or buffs for example... this usually leads to both of you thinking you wiped or controlled the opponent's field of creatures and have a healthy field on your own end, and the game responds by respawning every creature that died to one of your desynched cards each and every time you kill it. You often notice that your opponent disconnects eventually... it's usually because on his/her end, they won the game.