Workie, as the animal is called, will star in a TV advertising campaign that starts on Wednesday evening.
Since 2012, 5.4 million workers have been signed up to a workplace pension, under the auto-enrolment programme.
But millions more people who work for small businesses, or individuals, have yet to be offered a pension plan.
All employers are being warned that they need to offer pensions to anyone who is over the age of 22 and who earns more than Â£10,000 a year.
That includes, for example, nannies, care workers, plumbers and bar staff.
The pensions minister, Baroness Altmann, was said to be "personally involved" in designing Workie.
A spokesperson for The Pensions Regulator said Workie was the embodiment of something you cannot ignore.
A ten foot tall hairy monster - reminiscent of Sweetums in The Muppets - is to be used to persuade more employers to set up a pension scheme.