[Image ID: Two traditional, fully coloured drawings of aliens from Half-Life, respectively showing a houndeye, and a bullsquid. The houndeye, drawn in a mosaic-like style, is yellow, orange and red, except for its stripes and eyes. Its stripes are drawn in blues and its eyes are blue, purple, and pink. The houndeye is suspended mid-air and viewed from the right side, one paw nearly touching the ground as it lands. It looks peaceful.

[Image ID: A GIF of a beta bullsquid. The beta bullsquid is a two-legged animal, with a long, thick tail and a head that connects directly to its body. It's yellow, smirched with black. Its face tentacles are all white. It's rotating horizontally, viewed from the side. End ID]

Heck yeah!! Thank you for asking :0

I have a theory about bullsquids: they came to xen from a different dimension than vortigaunts and houndeyes. Mainly, this theory is based off of the limb differences of the creatures: houndeyes and vortigaunts have uneven numbers of limbs on average (with houndeyes being tripods, and vortigaunts having 3rd arms). Meanwhile, bullsquids and headcrabs have a relatively even number of limbs (2 legs excluding tail for bullsquids, and an arguable number of limbs for headcrabs but it's seemingly even). This isn’t all the xen creatures, but it’s what I conside the ‘main 4’. Additionally, while it’s functionally impossible to tell what creatures came from where, and most if not all of this can be attributed to design choice, I think bullsquids came from a different dimension because of how they look in general. Instead of having central eyes (whether compound or seperated), their eyes are on the sides of their head, and they seem to lack center features, mostly. (Especially when compared to typical ‘xen’ creatures, such as the alien grunt, the alien controller or vortigaunts.) This is mostly just me thinking about the origin of Xen creatures in general but!! I think it’s fun to think about :0