Weak Morlox are level 90 aggressive Mini-Bosses located in Mindos Cave on Loto Island. They are part of the Find Bob's Brother! quest.
Players must go down the vines slightly south of the entrance in Mindos Cave and traverse a walking puzzle to get to the south side of the room, where a telepad will lead to the Morlox. There are three different ones (see images below) that must be consecutively killed for keys leading to the next and finally, Bob's Brother.
The Three Morlox
The first Weak Morlox is green and drops Key #1 that unlocks the gate just north leading to the second one.
The second Weak Morlox is red and drops Key #2 that unlocks the gate just north leading to the final one.
The third and final Weak Morlox is blue and drops a Mindos Orb that allows the player to use the southeast telepad leading to Mindos Cave #3, where Bob's Brother is located.