This is a phrase widespread in the Linkin Park community. The phrase is a misheard lyric from the song “When they come for me” by Linkin Park, Where Mike Shinoda says “Try to catch up motherfucker”. Many
people misheard this line as “Try the ketchup motherfucker”. It’s also comical with many
people joking that they
will try Mike Shinoda’s “ketchup” or Mike Shinoda “poisoned” the ketchup etc. The phrase is used randomly as it is in the song.