A couple of other instances include the competitiveness he displayed in Aerodynamics (anything Jeff and Troy were doing became a competition- “I’ll smoke you two under the table”). Pierce may also still be using pain killers further altering his personality. Also his anger is probably more directed at Jeff than anyone else. Pierce has displayed increasing animosity towards Jeff the last couple of episodes; like blaming him for keeping Rich out of the group and asking Annie to give him Jeff’s leather jacket in the drug play.

Nerd mode still on: Chang as a Drow (rhymes with cow!) is the most awesomely spot on thing this show has ever done.

Nerd mode off.

As to Pierce’s behavior, it is certainly monstrous. But it is by no means unsupported…

Lost mode on:
Many complained that in Season 1, Pierce and Shirley were the least connected characters in the show. Either they got the A-story (though partnered with Jeff/Annie) or they were completely forgotten.

This year, Harmon has taken those complaints to heart, as Shirley and Pierce’s arcs are actually the driving force behind the season. Check it:

Shirley’s pregnancy drama is self-evident. But Pierce’s abandonment issues have taken up most of the season:

The Psychology of Letting Go got the ball rolling with his mother’s death, leaving the study group as the only people he has.

Basic Rocket Science showed that Pierce is a ball of unsettled issues – even if we didn’t realize it at the time. Note Pierce’s father’s character design in Celebrity Pharmacology last week and then note exactly when (and with what dialogue) he goes off the deep end in Rocket Science.

Messianic Myths had Pierce try to reach out to other people closer to his age… and was quickly abandoned by them.

By Aerodynamics Pierce has broken, and is actively attempting to force his way into activities he’s been left out of (here the trampoline).

And then we get to Mixology. The study group’s behavior to him in Mixology is frankly monstrous, and if his behavior in AD&D wasn’t to an innocent third party, almost justified by it:
First, they forget his birthday. Second, they give him the option of either stating he’s senile or being cast out of the group. Finally, he’s abandoned in the bar entrance, and completely forgotten about (and you can argue whether Shirley freeing him was only because she had to to get out).

Christmas: Sure, Pierce tries to explain it away by looking for more cookies, but odd that he’s the only left when Abed faces his abandonment issues head on.

Population: Was Pierce revealing the Shirley/Chang bit out of spite or just because the gang wanted to exclude a new person (Rich) when the existing gang has obviously failed him (again, see Mixology).

Pharmacology / AD&D: Self evident.

Or to review, 9 out of 14 episodes have dealt with Pierce’s abandonment arc. And the audience has mostly missed it.

Spot on comparison of Pierce with Cartman, James.