Dic: run wild, run riot

▷ run wild :
a) to grow without cultivation or care
b) to behave without restraint

▷ run wild : If someone, especially a child runs wild, they behave as they want to and no one controls them.

▷ If something or someone, especially a child, runs wild, they behave in a natural, free, or uncontrolled way.

• Everything that could grow was running wild for lack of attention...

▷ run riot and run wild: Fig. to get out of control.

• The dandelions have run riot in our lawn. 
• The children ran wild at the birthday party and had to be taken home.

▷ run riot
1. if people run riot, they behave in a way that is not controlled, running in all directions or being noisy or violent

• I dread them coming round because they let their kids run riot.

2. if your imagination runs riot, you have a lot of strange, exciting, or surprising thoughts

• My imagination was running riot, thinking of all the ways that I could spend the money.

... Collins, CALD, Cobuild,  

McGraw-Hill Dictionary of American Idioms and Phrasal Verbs, 

Cambridge Idioms Dictionary