I spotted this a while ago, but keep on coming back to it - the Adipose Stress Toy.
The Adipose made their debut at the same time as Donna Noble, and although technically they are quite gross (born from the fat and yuck of humans), they are also enormously cute.
Far from having to squish and squeeze the stress away, simply looking at the Adipose’s toothy grin makes me feel happy.
From the site:
Now, with these adorable Adipose Stress Toys you can have your very own Adipose, without the need for taking questionable diet pills, or undergoing Parthenogenesis. These officially licensed stress toys are sure to be a hit with any Doctor Who fan, and their massively malleable forms will have all those worries and cares melting away, just like the dieters fat melts away into the Adipose in the TV show.
I am sold!