You Do Need power plug adapter while traveling from Cocos (Keeling) Islands to Lebanon.

Here is Why You Need An Adapter

The outlet and plug type used in Lebanon are C, D and G and in Cocos (Keeling) Islands is I. This is how they look like.

Cocos (Keeling) Islands

In Cocos (Keeling) Islands, outlets of type I are in use.

Type I

Lebanon

In Lebanon, outlets of type C, D and G are in use.

Type C

Type D

Type G