This Claptrap unit needs some putti, which you can get from damaging the Opha Guardian creatures with elemental weapons and then meleeing them. The only problem is that the Opha are not in Tycho’s Ribs, but in Eleseer, the last area of the game. If you follow The Beginning of the End mission, then you’ll be visiting Eleseer anyways.

Once you get there, head to the end of the first path you see to get an Opha that will continually spawn. You will notice on your objectives list that you need to get four different kinds of elemental putti, meaning you will need the four elemental weapons. In order to get the putti, all you have to do is inflict that elemental damage on the Opha and then melee them until they drop the putti.

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Inflict the elemental effect on the Opha, then melee them to get that respective Putti.

Whenever you manage to get two of each elemental putti, bring them back to Z8N-TP. A problem arises, though, as the putti will start attacking, so destroy them all and then talk to the Claptrap unit afterwards to finish the mission.