Ectoplasm
Ectoplasm may refer to:

Biology
Ectoplasm (cell biology), the outer part of the cytoplasm
Ectoplasm, outer layer of soft tissue in foraminiferans

Art and entertainment
Ectoplasm (radio show), BBC Radio 4 comedy series
Ectoplasm (My Hero Academia), a character in the manga series My Hero Academia

Other uses
Ectoplasm (paranormal), physically sensible phenomenon claimed to be due to "energy" described as paranormal