Dupli-Arms grants Mezo arm-attached tentacles that can replicate parts of his body.
Mezo is able to reproduce any of his body parts, including ears, eyes, mouths, hands and so on, with said parts taking form through pods located at the tip of each of his tentacles.
The duplicated parts are actually enhanced versions of the original ones, granting Mezo improved strength and senses. Different parts can be manifested at once too, allowing Mezo to combine his augmented sensory abilities.
The tentacles, just like any part of Mezo's body, are vulnerable to injuries coming from enemy attacks. The same goes for the replicated body parts.
Dupli-Arms makes Mezo excellent for spying and stake out missions, as his tentacle-created parts have heightened functions. As examples, with his eye replicas, Mezo has full peripheral vision, being able to see anything within a 360º field of view, and with his ear duplicates, he can detect sounds from sources behind walls or far away from his position.
For combat, Mezo multiplies his already great physical strength by replicating his arms. Mezo is strong enough to carry people on his back, and with the help of his tentacle arms, he is capable of shielding or hiding them from view.
It's worth noting that the tentacle pods responsible for recreating Mezo's body parts can do the same with themselves as well, meaning that Mezo can continuously extend his tentacles by just making his pods self-replicate over and over. Additionally, one pod can reproduce multiple separate organs, but doing so makes the duplicates less efficient.
Thanks to the fact that his tentacles are webbed, Mezo is able to temporarily glide through short distances.