Bido was a chimera created in the Fifth Laboratory; after escaping it, he followed the homunculus Greed. Before his transmutation, he was a member of Martel's military special ops team which instigated the Ishval revolt. He was fused with a lizard or a gecko; this enabled him to have a firm grip on surfaces when climbing, and to use his tail as a bludgeoning weapon. He is bald and speaks in a raspy, hacksaw voice, though it's unclear whether this is a result of the fusion or not.
SpoilerIn The first anime he is killed by the military. In "Brotherhood" he survives instead of Martel. He searches for Greed and finds him in Father's lair. Unfortunately, the homunculus has forgotten about Bido and kill him. Afterwords, Greed's old memories start to return and Greed realizes he has killed the last member of his family with his own hands.