Growling kitten

[H&SWells]

in an attempt to keep the two monsters entertained yesterday i brought out a couple of new toys. Eric, the red immediately took charge of a fur ball and spent the next ten minutes walking around with it in his mouth growling..... thought that this might be a one off so took it out again last night and same thing happened. OH insisted i took it off him, bit of a battle ensued. My question is should this toy be banned, which is my OH opinion, or should i just try to find another one so that Ernie doesnt feel left out ? Is this normal behaviour or could this toy become an obsession with him.