Thunder Punch was funny. Emphasis on was. I'm sure lawnmover was also funny, but I can't for the life of me remember when because it was so long ago.
Honestly, the best thing for lawnmover right now is to become sort of a background meme like Thunder Punch and all those other ones I can't recall right now. I'm only getting rid of the lawnmover group because it's stretching things a bit too far (Thunder Punch never had its own group; and anyway Lawnmover never really did anything to deserve it) but I would never consider stopping anyone from using the lawnmover meme because I'm for freedom of speech.