How can I make a o2 cheater for a 1996 Subaru legacy outback 2.2 check engine light 0420 code?

Have you replaced the forward O2 sensor yet? Many mechanics jump to the conclusion that P0420 means a bad converter, but it really means the converter is not able to digest the exhaust. Because converters normally last twice as long as O2 sensors it is always a good idea to replace the much cheaper forward O2 sensor first. If you have a 15 year old O2 sensor in the front it is sluggish as a pig for sure.