The Deku Baba is a plant that springs to life when Link gets near it. They will lunge at Link with their heads. Link first runs into them on the path to the Great Deku Tree (Withered ones), although those ones will not attack him (you only get damaged if you run into them). It is Inside the Deku Tree that Link will run into the attacking variety.
When they lunge at you, they will usually leave their heads on the ground for a second or so; if Link hits them with his sword at this state, they will stand straight up. When they are killed while straight up, they will drop a Deku Stick. Attacking them normally will usually yield Deku Nuts when killed.
