[Morph Mod]

There is the Lib Disguise plugin, but it is missing features and fun things that Morph includes. You can use mob abilities is one main one. And also the mob does not lag behind you. Plugin Page: 

 https://www.spigotmc.org/resources/morph.8846/?__cf_chl_jschl_tk__=ae36207e602ae378196e76d95b8530363e8f9871-1611527907-0-AWF1aJKNKK1a66G-HTd8xXHgAPDaI0PjV3c6J1-PM0a5jHX8IXsvQiHP5hJ5ehO5Fk3gFPsdD1_UHr6QLtzqYXs4jNKlW5XucEPM6QLft9q9nwtTQo7Tjzp4nsZh-KROeBXtIRhPJac_Lr8TH-tTxb8R6jtfSre570uHcZ9jPfC66Ee04-f2uounMpA5JhJsN7AXT3v3huM5s8qUChk6vSSsURtWacRM-2KnT14pQwcXjEJdwIpspo26Sy06clON-gZ8JeoZSGeCTVUF4z2X8PdA2ezw6dNP6JiOYXKPZBImGnYBB-lRHKAc-zGNmSN-vFP6UA5n_ZaoAaChaQ2uymc

[Datapack]

you will probably have to make a skript and download the skript plugin