Using Xinglong observatory's Ground-based Wide Angle Cameras (GWAC), astronomers from China and France have detected a new superflare of an ultracool star known as SDSS J013333.08+003223.7. The newly found event, designated GWAC 181229A, appears to be one of the most powerful flares on ultracool stars so far discovered. The finding is reported in a paper published December 28 on arXiv.org.