You can not get Celebi in the Ilex Forest. The only way to get Celebi was from a Wi-Fi Connection with GameStop or EBGames. But the event is now over.
Celebi is the protector of the Ilex Forest.
The legendary forest Pokemon would most likely be Celebi. As well as being the time-travelling Pokemon, Celebi is also a protector of the forest - most notably Ilex Forest (in Pokemon Gold, Silver and Crystal). No other legendary Pokemon is linked to any forest in such a way, so Celebi would have to be it.
You get it in Ilex Forest.
in ilex forest by special event from the next Pokemon movie event.
That would be Celebi.
Celebi
Celebi is found in the Ilex forest near the 2nd Gym, at the shrine
You can only find celebi through an event in the ilex forest.
Go to the shrine on ilex forest. Talk to it!
The gaurdian of the Ilex Forest is Celebi.
A special event in ilex forest
take the GS ball to the shrine in ilex forest