Magnetoelectricty in antiferromagnetic Ni$_3$TeO$_6$ with chiral and polar lattice

Ni$_3$TeO$_6$, crystallizing in a polar and chiral lattice structure ($R$3 space group), becomes antiferromagnetic below $T_N$ = 52 K. It was reported that magnetic field-induced spin flop transition below $T_N$ accompanies a record-large non-hysteretic magnetoelectric effect (1300 ps/m). Here we present comprehensive magnetic, electric and structural properties of Ni$_3$TeO$_6$ single crystals for magnetic fields up to 92 T and temperatures down to 1.5 K. We discovered an additional sharp field-induced phase transition at 55 T, accompanied by a colossal change of electric polarization - the largest magnetically induced polarization change observed to date. We interpret our data with the help of density-functional calculations and construct a microscopic model across the whole magnetic field range.