Hello everyone, nice to welcome you on our site, this page even has Level 13 answers. I enjoy it =D
Level 13 - URGBAATA
The answer to this puzzle is:
Words: RATBAG, RABAT, ABUT, TABU, GRUB, GUAR, GARB, BRUT, BURG, AGAR, TRUG, TUBA, GRAT, GAUR, BRAT, BURA, RAGA, GAR, RAG, GUT, BAG, BAR, TAU, GAB, GAT, RUG, RUT, TUG, ARB
Bonus words:
RATBAG, RABAT, ABUT, TABU, GRUB, GUAR, GARB, BRUT, BURG, AGAR, TRUG, TUBA, GRAT, GAUR, BRAT, BURA, RAGA, GAR, RAG, GUT, BAG, BAR, TAU, GAB, GAT, RUG, RUT, TUG, ARB