in some servers you can summon cursed man or pets generally without the sacrifice of one mob (with the exception of reanimated man which you cant summon it without sacrifice)in olumpiad games..when you summon it let the pet w8 outside the arena and you w8 inside arena :P ...server will recognise that your pet does NOT compete in the olumpiads so it ll get invisible for your opponent. :o of course you ll be able to see it but your opponent wont!MAKE IT ATTACK YOUR OPPONENT....
note:if your opponent try to /target summon pet will be untargetable because you cant fight something you cant see ;D :D...(ex you cant target a gm if he is invisible so the pets do)