Name: synaptic leeches
First Appearance: U.S.Agent (vol. 2) #2 (Sep. 2001): "Powerplay"
Super? (Has Super Powers/Special Abilities/Technology): Yes
Number of Appearances: 2
Note: scorpion-like; alien creatures or designed by SHIELD
Synaptic leeches are creatures that burrow under a victim's skin and place that person under the control of a person in symbiosis with the mother leech.
An Atlantean named Morcan made a deal with the villain named Poundcakes to buy synaptic leeches, no doubt for nefarious purposes.
Suggested links for further research about this character and the character's religious affiliation: