Ilex Forest is a winding path through dense trees connecting Azalea Town and Route 34. There are many patches of long grass on the ground where low-leveled Pokémon can be found. Travelers can enter at either end with no trouble at all, but to pass through to the other side they must be able to use the move Cut outside of battle.
When the player enters the forest, the only way to proceed through the next section of the forest is to return the runaway Farfetch'd to the regional cutting master's son, thus receiving HM01 Cut as a reward, allowing the player to clear the path from a cuttable tree. There are two Farfetch'd and each needs to be approached while they are facing the other way. The player can do this by walking over sticks and, by doing so, causing them to ruffle. This grabs the Farfetch'd's attention and, if no other sticks are ruffled, may allow them to be approached from behind.
In the center of the forest is a man who will teach your Pokémon the move headbutt via move tutor, multiple times, for free. Using Headbutt on one of the trees in the forest can sometimes yield a wild Pokémon, which Trainers may wish to capture.
When you reach the guardhouse in between routes, talk to the women behind the counter and she will you TM12 to help you complete your Pokédex. TM12 is the move Taunt, a dark-type move that causes the foe to only use attack moves. The effect lasts two turns or until the foe switches out. Taunt can be used on a foe with a Substitute. On the turn that Taunt is used, if the Pokémon using Taunt goes before the target and the target selected an non-attacking move that turn, the move will fail. If the target is holding either Choice Band, Choice Scarf or Choice Specs on a non-attacking move, or only knows one non-attacking move, the target will be forced to use Struggle until the effects of Taunt wear off.