The Fosters Effect was an magic reaction discovered and calculated by Dr. Foster quite some time back. When Dr. Starfinder and the students on Weirdsister College teleport a Australian woman (Supposed to be Foster's assistant), they try to build a device that can find a way around Fosters effect. It is later revealed that the Australian woman is infact Dr. Foster. The Fosters Effect can happen when casting too many spells. With all that energy flying around at the same time, magical paths cross over and cause something known the Fosters Effect. This reaction causes spells to multiply out of control, and has created all sorts of natural disasters. Using magic for selfish and trivial ends can also cause the Fosters Effect. Misgone Magic was what they used to call the Fosters' Effect in the Middle Ages.
When Miss Cackle teaches her students about the Foster's Effect, she tells them a ryhme about Dr Foster trying to stop the rain, but ending up in a bottomless puddle instead. This is based on an old ryhme: 'Dr Foster went to Gloster, In a shower of rain, She Stepped in a Puddle, up to her middle, and never went there again.' Miss Cackle refers to the rhyme in spells class, saying that Foster's use of magic caused the giant puddle.