A school in Essex kept pupils indoors for a day after a 3.5 metre snake was seen slithering towards their grounds.
On Tuesday Friars Primary School decided to keep pupils inside during break-time, after a street cleaner spotted the reptile loitering nearby.
Head teacher Anne Germanacos told Newsround a wildlife expert had scoured the school grounds but found nothing.
Pupils are now being allowed outside to play, but have been ordered to stick to the concrete and not walk on the grass.
"It could be anywhere in Shoeburyness or it could have left by now," said Mrs Germanacos.
The dark-coloured reptile was spotted by cleaner Jim Garrod near Elm Road.
Mr Garrod, who keeps snakes, said he froze when he saw the animal, and then watched it wriggle off towards Friars Primary School.
Essex police are appealing for anyone who sees the animal or anyone who has lost a pet snake to get in touch with them.
Mr Garrod said: "This one could have been a Boa Constrictor or a very big Python."