The, uh, the gonarchs, the 'adult headcrabs' on Xen?
Yeah, it literally just is giant walking ballsack, pretty sure the concept artist basically just says that directly in 'Raising the Bar'.
A bunch of the planned enemy types that existed in the beta/alpha, before Valve/HL2 got hacked and they significantly shifted development... a lot of the enemy types had concepts of much more fleshy/flappy/foldy appearances, often with hair, again, like pubic hair.
But they toned that down a lot, made them much sleeker, more 'synth' than ... i guess monstrosity.
But but, then of course, Eli gets skull fucked to death by a giant penis tentacle, extending out from... basically a giant floating testicle sans scrotum, in Ep 2.
