A "heavy muon" who could stand to lose a little weight, TAU is also part of the Lepton 6-pack.
Tau is a heavyweight particle plush but also comes in a lightweight shipping saver version which is especially nice if you live outside the U.S. So if you prefer it to be filled with lightweight stuffing, just choose that option at checkout and it will only weigh in at 2 oz. Of course you won't get the full effect of its Tau massive weightiness but it will be the same in every other way.
Approximately 7 oz (198 gm); 4 inches (10 cm) across.
For ages 5 and up as it contains glued-on/small parts.