Jingle Jim is an evil elf whose real name is Mijel Gnij. He was kicked out of Santa's workshop and swore revenge by reappearing every 100 years on Christmas. He gives 100 people one of his 100 presents that twists their wishes against them. By midnight, the spells will be permament.
He appeared in All I Want For X-Mas where Martin bought last-minute presents from him. Martin got one for himself and gave the others to M.O.M., Diana, Java, and Billy. MOM wished for no caroling, so she had to speak in song. Diana wished for peace and quiet, so her ears grew and became sensitive to all sound. Java wished for a white Christmas, so he experienced a heatwave. Billy wished for a Christmas with Martin, so he became stuck to his back.
They found Mijel at Santa's workshop and he froze them in place with snow. Martin used his present to wish for a paranormal Christmas, which reversed the spell and freed them. Mijel disappeared at midnight.
Jingle Jim's spell: Christmas comes but once a year. A time of merth, good luck and cheer. But when the clock strikes midnight clear, A big surprise awaits you here.