As many are using skill drain against the current meta,i will be writing a post on its rulings so that duelist may clear their doubts and avoid future misplays.

Effect: Pay 1000 Life Points. The effects of all face-up Effect Monsters are negated.

sources from PoJo and Yugioh Wiki:
one very important criteria in order for skill drain to negate the effect of a monster is that the monster must remain face up on the field when it's effect resolves for it to be negated. Continuous effects of monsters will also be negated. Skill Drain does not negate maintenance costs(eg cards like core chimail), nor does it negate conditions placed on monsters or tokens (eg. debris dragon, scapegoat).

also do remember that skill drain DOES NOT prevent the activation of effects,as the following example will show.
Example 1: Exiled Force is on the field along with an activate skill drain. Since skill drain does not prevent effects from being activated, you can activate exiled force's effect tributing himself as a cost, and targetting a monster on the field. When the effect resolves, exiled is no longer face up on the field, so it's effect is not negated.


Example 2: Snipe hunter is on the field. His effect is activated: a card is discarded and a target is picked. Skill drain is chained.Nothing else is added to the chain. Skill drain resolves, and applies its negation effect. Snipe hunter's effect is now negated.

see how this goes now?hence it explains why rescue cat escapes skill drain,because skill drain has to fulfill 2 important conditions.it does not prevent the activation of effects and the monster must remain FACE UP on the field when its effect resolve.when rescue cat's effect resolve,it is no longer face up on the field,so skill drain cant negate it.

further rulings:
1.Paying 1000 Life Points is a cost.
2."Skill Drain" negates the effects of face-up Effect Monsters on the field, but does not negate effects that activate in the Graveyard, such as "Witch of the Black Forest", "Sangan", "Mystic Tomato", "Giant Rat", "Sinister Serpent", and "Vampire Lord".
3."Skill Drain" has no effect on "Stardust Dragon". For the first effect, tributing "Stardust Dragon" is a cost, so "Stardust Dragon" is not on the field and is unaffected by "Skill Drain". The second effect activates in the Graveyard, so "Skill Drain" cannot negate it.
4."skill drain" allows gladiator beast to tag out,as the gladiator beast is no longer on the field when its effect resolves.however when another gladiator beast tags in,its effect is negated by "skill drain".


of course the list of rulings are not exhaustive,i just mention the important ones that most people tend to forget or overlooked.