A portmanteau is a type of compound word that fuses the sounds and meanings of two component words; for example, frenemy (friend + enemy) or smog (smoke + fog). We develop a system, including a novel multitape FST, that takes an input of two words and outputs possible portmanteaux. Our system is trained on a list of known portmanteaux and their component words, and achieves 45% exact matches in cross-validated experiments.