Billy forgetballs: Can i have an Unusual Team Captain? PLZ?
Heavy: NO!
Billy forgetballs: Aww...
Guideline Engineer: Dont worry, i never got one either.
Billy forgetballs: So...how do we deal with the zombies?
Scout: Their difficult to kill, that's for sure.
Demoman: It seems only head shots can kill them. Or blowing them up with explosives. Cutting them in half just causes their torsos to continue crawling after us, so a decapitation is necessary...
Heavy: In short, if you have poor aim, you might as well be dead.
Billy forgetballs: So...What are all of you doing here? and Why with RED?
Heavy: We are the only survivors, so far. We barricaded ourselves in here to be safe from the zombies. But it may not hold forever, and we are limited on ammunition.
Billy forgetballs: *gasp*
Billy forgetballs: Sentry Gun!
Professor Engi: Don't worry, it wont harm you.
Billy forgetballs: Who are you?
Professor Engi: I am Professor Engi. I'll explain everything.

Billy forgetballs: So that is our situation...
Professor Engi: Yes. But your little knife wont do stuff against the infected. You'll need something more useful. Take whatever you need.
What melee weapon should billy use? (any TF2 Melee)