What episode is this?!


Hey guys. I'm new to this site. I actually only made an account because I have a question about an episode that's been driving me nuts lol. I've seen every episode of each season and I saw like 30 seconds of this specific one on tv this week. I can't remember which one it is but I wanna watch it again. All I can remember is Ryan working in the lab on something and Walter sneaking up on him and scaring him, or something like that lol. Ryan says something like "What are you 8 years old" and Walter says "7".....it made me crack up and wanna watch the whole episode again but like I said I can't remember for the life of me which one it was. Any help? It would be greatly appreciated! Thanks
I think that's episode 10.02 "Stiff". :)

(Aw man, now I'm missing Walter and Ryan's banter. Loved them!)