[akomtu]

You should've played the game and claimed you've never said what HR says you've said and in fact (here goes the distraction part of the lie) you heard another guy was talking about pizza, so HR must've overheard that conversation and misremembered the details.

[winrid]

The problem is the manager would probably start with "did you have a pizza stolen?" without mentioning HR

[psd1]

The stolen item needs to slightly vary in each telling. Catch a mole 101.

[greedo]

They'll have to call it the "Pizza Trap" instead of the Canary Trap...

[akomtu]

From this question alone you could figure who's trying to backstab you.