The Serpent Squad is a fictional mercenary group composed of snake-themed criminals appearing in American comic books published by Marvel Comics. Most often antagonists of Captain America, the roster has changed through various incarnations.
Cover art for Captain America (vol. 5) #28, art by Steve Epting
The Eel is an alias used by two fictional characters appearing in American comic books published by Marvel Comics. The first character to take up the identity was Leopold Stryke who first appeared in Strange Tales #112 created by Stan Lee and Dick Ayers, while his successor, Edward Lavell, first appeared in Power Man and Iron Fist #92. Both Eels were at one point members of the Serpent Squad even though the character they portray was not actually based on a snake, but on a fish that resembled a snake. Neither Eel has ever been featured as a regular character in any of Marvel's ongoing or limited series.
Cover art for Captain America (vol. 5) #28, the Eel is at the bottom left, art by Steve Epting