Kitty-cat?
Grass hopper?

I was also thinking a cat. Maybe a rabbit? Some type of small mammal probably. Grasshoppers are another possibility, but they usually make holes, not clean cuts (but they have the appetite of a small mammal for sure!).

Cut worms are known to do that to vegetable seedlings early in the growing season.

I've seen something similar with first season sabal palmettos --eaten off just above the soil level.