A 13 year-old boy was allegedly king-hit on Saturday, while enjoying an afternoon at Splash Planet with family and friends.
It is believed the victim did not know the 14 year-old boy who is alleged to be responsible for the attack.
The victim, who was sitting at the time, had to be rushed to hospital after suffering a seizure and passing out.
It is unknown if the victim has been discharged from hospital.
It is also believed the alleged offender threatened to stab another boy, before hiding from police.
Hastings Mayor, Sandra Hazlehurst said 3500 people attended Splash Planet on Saturday.
"Our Splash Planet is fantastic for families and staff work really hard to ensure it is a safe place for all who visit. Security is paramount to the success of Splash Planet. Our staff handled the incident very well."
"Security is hugely important to us and to ensure that no incident happens in the future. Staff make sure Splash Planet is a safe facility for families."
She said she had not heard of an incident like this happening and they had taken it "very seriously".
A similar incident occurred in the early hours of October 15, where 14-year old was left bloodied and beaten in a Flaxmere park.
-Hawke's Bay Today