Digging isn't working. He isn't good at it, anyway, but even if he was, he just isn't big enough or strong enough to dig like this, not to get to Lauren, but what else can he do? His magic isn't helpful here... Except maybe one thing.

He's not as good at shapeshifting as Lauren, having to use a spell to do it instead of just doing it naturally, but he can still do it, and animals are much better diggers. Living in the forest, the first animal that comes to mind is a badger, something he's seen around before, and so he only pauses his digging a moment, still ignoring everyone else (except Papyrus), so that he can cast his spell. Of course he's trying to be a big badger, so he can dig faster (because that's kid logic for you) and although he definitely is large for a badger, as large as a medium sized dog, he could still be lifted by the others if they try.

For now though that isn't on his mind, and all he does is set back to digging.