Might be overtrained use strength 0.6 to get smooth results on realistic style
For drawing style a strength of 0.8 should do fine

Use "Scrappy-Doo" tag to get Scrappy-doo
Use "Monster Scrappy-Doo" tag to get Scrappy Rex
Use "Scrappy-Rex" tag to get Scrappy Rex on illustrious version

Usefull tags:
Scrappy-Doo,Realistic,Dog,Furry,Brown Fur,Brown Eyes,Brown Bumpy Collar,Brown Collar
Monster Scrappy-Doo,Scrappy-Rex,Realistic,Dog,Furry,Wine Brown Skin,Yellow Eyes,Fat,Muscular,Sharp Teeth