I love coins like this, there are multiple errors occurring here, which you have to unravel a bit to figure out the chain of events. The coin in question is a 1981 cent. First, it was struck on a split planchet, which was split before the strike. The zoom photo shows this fantastically (weight is 1.21 grams). Second, it was struck about 15-20% off-centre. Third, it was struck overlying a blank planchet that was normally loaded in the striking chamber. The reverse is fully struck, with no indications of any obverse design on the obverse. Bear in mind that in Canadian coins, the reverse is the hammer die. A split planchet was partially (mostly) fed into the striking chamber on top of a normal blank planchet, then the strike, with the collar forcing up the lip.
