The Post Hoc Ergo Propter Hoc fallacy is thinking that since B followed A then B must have been caused by A - correlation is not necessarily causation.
It is Latin for ‘after this, therefore because of this.’1
A simple example is “the rooster crows immediately before sunrise; therefore the rooster causes the sun to rise.”1
Post hoc ergo propter hoc - Wikiwand ↩ ↩2