Niobe and Ghost's running animation. In short, it makes it look, in the words of one online review, like they have broomsticks shoved up their butts, or are desperately trying to get to a bathroom.
Sparks. He was obviously meant to be the comic relief and it shows:
In the first mission he asks Niobe and Ghost how they'd like to be buried when he carts their bodies back to Zion and asks Ghost if he can have his boots should he die.
After a particularly long journey through the Merovingians chateau Niobe calls Sparks to ask if the exit is clean.
Sparks: As vestal as my bunghole.
During the freeway chase as things start to heat up, Sparks calls Ghost.
Sparks: Can I have your personal processing unit?
After Morpheus asks Niobe and Ghost to assist with the plan to get Neo to the source by blowing up the nuclear power plant Sparks unloads on them with a rant about how they're going on yet another suicide mission:
Sparks: I know you're both listening to me about as much as you're listening to this pole here, so I'll just tell you what I think. I think you just spent eight of your nine lives getting out of there, and if you turn around and go right back in, I don't think you're just pushing your luck, I don't think you're crazy... I think you have a death wish! A major, full-on Bronson! Since your lives obviously mean nothing to you, I ask you... try to think about something that does have meaning... Namely my life.
Ghost: Sparks, shut up.
Sparks: ...yeah, sure, why not.
If you know what you're doing with the hacking minigame, you can actually get into contact with the Nebuchadnezzar and the Logos and have an IM conversation with Trinity and Sparks respectively. In the middle of your convo with Sparks, he'll say he just got a file from you, and when he opens it up it turns out to be a trojan horse. Sparks panics and says you need to act fast before the Logos crashes. But it turns out he was just joking. That's right, Sparks just trolled you!