A kind of DNA transposon that populates the genomes of protists, fungi, and animals, characterized by a unique set of proteins necessary for their transposition, including a protein-primed DNA polymerase B, retroviral integrase, cysteine protease, and ATPase. Polintons are characterized by 6-bp target site duplications, terminal-inverted repeats that are several hundred nucleotides long, and 5'-AG and TC-3' termini. Polintons exist as autonomous and nonautonomous elements.