Lava from the volcano in La Palma in the Canary Islands plunged into the sea at around 23:00 local time on Tuesday.
Columns of thick black smoke shot into the air when the red hot molten rock rushed off a 100 metre high cliff near playa Los Guirres and smashed into the sea.
The Authorities have been worried that this could happen since the volcano erupted on Sunday, September 19, because when lava meets salt water it causes toxic clouds.
A two-mile exclusion perimeter has been set up and the emergency services have told people to keep away.
"Anyone nearby should take refuge and people should not approach the area under any circumstances,” said the Canary Islands Emergency Coordination Centre, Cecoes-112.