Monstrosity master

You have become a master of training and taming unusual and anomalous creatures. You gain the following benefits:

• You gain proficiency and expertise with animal handling if you don't already have them
• Monstrosity call: Once per Short rest, you can call out to a monstrosity to attempt to make it friendly towards you. You target one monstrosity with intelligence of 6 or lower and has a CR of half your level or lower (rounded  down) you can see, it makes a wisdom saving throw (DC 14 plus your prof mod) and if it fails, it becomes friendly towards you. (If it Succeeds nothing happens) after a week spending time with it, it can become either a mount or companion. It cannot have a swimming or flying speed unless the character owning it naturally has the same one.
• You can use spells that list beast monsters on a creature you've used "monstrosity call" on

NOTE: Towns and Villages might not appreciate a strange creature owned by a potentially dangerous Warrior or mage on their land 

SECOND NOTE:  here are some extra monsters that your DM might let you use "monstrosity call" on as well: hellhounds, wyverns, shambling Mounds, ochre jellys, gelatinous cubes, black puddings, and gibbering mouthers. (Only allow these when they are level appropriate.)