The best replacement for doo is polaris.

The best alternatives to doo are rated as following:
★★★★★  polaris
★★★★★  arctic cat
★★★  spongebob
★★  idocument
★★  poo
★  marmaduke
★  waverunner
★  jet ski
★  yamaha jet ski
★  polaris snowmobile
  polaris snowmobiles
  yamaha snowmobile
  sugar sand
  snowmobile
  wave runner
  new scooby doo

Your alternative for doo is not listed? Suggest!
Speaking about doo, one probably shouldn't forget about batman and robin.

Other search terms related to doo and their ratings are:
★★★★★ batman and robin
★★★ scrappy episodes
★ daphne
You have in mind a companion for doo and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of doo in all years. Click on graph for more.
doo
polaris
arctic cat