While octopuses are generally pretty smart, Topo has proven to be quite exceptional. Born near the undersea continent of Atlantis, he has assisted Aquaman in many adventures and appeared assisting other heroes as well. He was supposedly taught archery by Green Arrow, understands basic construction, is a trapeze artist, and knows how to play (at least) 5 different musical instruments simultaneously. His touch is sensitive enough to know when a person is lying.
Topo was created by Ramona Fradon and first appeared in Adventure Comics #229 in October 1956.
After Infinite Crisis, Topo appeared as a humanoid/octopoid character in Aquaman: Sword of Atlantis. His name was a tribute to the original Topo. They are not the same character.
Topo appears in the New 52 as a colossal octopus looking behemoth. He is an ancient guardian of Atlantis and answers to its King, through the use of a special shell. He is still an old friend of Aquaman. During Scavenger's attack on Atlantis, Aquaman summoned Topo who proceeded to obliterate his entire fleet.
Powers & Abilities
Topo has demonstrated some telepathic abilities himself; being able to communicate with other sea creatures and even to receive thoughts from other people, such as Green Arrow while Aquaman is not present. As a aquatic sea life, Topo is extremely talented, displaying his remarkable intelligence and problem solving skills. He is shown to have been trained in archery and can play multiple musical instrumentals simultaneously. Topo has also shown great strength, as you may expect, he's a sub-mariner, and has showed minor shape-shifting.
The reintroduced Topo is gigantic, intelligent and extremely powerful.
He can withstand exploding submarines, each of his tentacles can crush a submarine, and he can defeat an entire fleet on his own.
Topo appears in the Young Justice Animated Series episode "Downtime" which is a screenplay revolving around Aquaman: Sword of Atlantis.