“He just wants to give us some hands-on experience, ” said Hermione, immobilizing two pixies at once with a clever Freezing Charm and stuffing them back into their cage.
So after that, you are not able to track that animal, unless you immobilize it again and put another one, meaning then you have to keep on doing the same.
Scar tissue's too deep. The heart's too weak to start up again, so you only immobilize the portion you're working on and you leave the rest of the heart on its own.
" See? This is a weak point, " he said. " If I fold it any more, you'll be immobilized" . He grinned his angel grin. " I won't, though, because it'd hurt like hell" .