I didn't expect that from the word ugralni. Is it then ugrok, ugrál, ugral...?
This is ugrik, not the related (but distinct) verb ugrál
It conjugates like a typical -ik verb. In singular: ugrom (or ugrok), ugrasz, ugrik. Plural: ugrunk, ugrotok, ugranak.
"Ugrál" is a frequent, repeated action, derived from "ugrik". If somebody keeps jumping up and down for some reason, then she or he "ugrál". For example, out of joy. "Örömében ugrál".
A good answer vvsey, thank you! That's why beside hungarian pools one can read: A vizbe ugrálni tilos.
That's why I couldn't get it together. Thank you jsiehler!