If you're interested in watching Tamil dubbed movies in Malayalam, here are some legitimate options:
Please note that downloading copyrighted content from torrent websites is illegal and can harm your device with malware. However, if you're still looking for options, you can try searching for Malayalam dubbed Tamil movies on torrent websites like:
Karya Umum 
Filsafat 
Agama 
Ilmu-ilmu Sosial 
Bahasa 
Ilmu-ilmu Murni 
Ilmu-ilmu Terapan 
Kesenian, Hiburan, dan Olahraga 
Kesusastraan 
Geografi dan Sejarah