Tailkinker

Chosen answer: It's not been made 100% clear. It was originally assumed that he actually consumed part of the brain, but this has turned out not to be the case. Sylar has been shown all along to have an instinctive knowledge of how things work and how to fix them - this is his actual original power and the ability that made him an exceptional watchmaker and repairer. It appears that he uses a similar process when acquiring new powers - he exposes the brain of the target, allowing him to examine it and determine how their power functions. He can then apply that knowledge to his own brain, allowing him to replicate the ability in question.

Tailkinker ★

Chosen answer: It's never explained. There are probably many fan theories, but none can currently be considered to hold any weight. With the catalyst lost when Arthur died (something confirmed by the writers), it is unlikely that the concept will be revisited at any point and thus the exact nature of the catalyst must remain a mystery.

Tailkinker ★

Chosen answer: Both, really. Peter is undoubtedly powerful enough to cause a serious problem, so nullifying him makes sense on a tactical level. It's also understandable that a power thief like Arthur could hardly resist the temptation to obtain so many new powers in one go when he's used to stealing them one at a time.

Tailkinker ★

Chosen answer: He's certainly been shown to use it to levitate, so full flight is probably within his capabilities. His exact limits are unknown, but are undoubtedly pretty high - he throws a police van around with no obvious effort towards the end of season one and has shown himself to be skilled enough to manipulate many different objects at once, as when he used the glass fragments against the invisible Peter Petrelli.

Tailkinker ★