T-Rex is broadening the sense of pal to take in everything except jerks and enemies — a definition by exclusion, as for forb here. This is reminiscent of the Facebook use of friend, which is much more inclusive than ordinary-language usage. (As a bonus, there’s protopal and autopal, with creative use of the prefixes proto- and auto-.)
In the third panel, T-Rex confuses the near-synonyms cyborg and robot, and in the next panel Utahraptor calls him on it. T-Rex then pines for a chip that would prevent such confusions.
Cyborg and robot are not only semantically similar, they share bits of phonological content. That makes this pair like others that have been discussed in the eggcorn literature, for instance in this Language Log posting:
I’m inclined to see [advent for event] as a simple confusion of phonologically and semantically similar words, like flaunt/flout, militate/mitigate, flounder/founder, etc. (Incidentally, it would be nice to have a technical term for these confusions. Let me suggest FLOUNDERS
A final remark: in getting the links for these two strips, I wandered through the Dinosaur Comics archives and discovered a great trove of linguistically relevant ones that hadn’t been posted on in Language Log or this blog. Really quite impressive. Well, Ryan North does have a master’s degree in computational linguistics.