Learn Spanish (Latin America): ¡Lo que engaña ese imán barato!

While you could say ¡Cuánto engaña ese imán!, using the structure ¡lo que + verb! is a very common and natural way in spoken Spanish to emphasize the extreme degree of an action. It emphasizes the extent of the deception, translating loosely to "The amount that that cheap magnet deceives!"

Why is the subject ese imán barato placed after the verb engaña?

In exclamatory sentences starting with words like qué, cuánto, or lo que, Spanish heavily prefers to put the verb before the subject. Saying ¡Lo que ese imán barato engaña! would sound very unnatural to a native speaker.

Doesn't engañar usually take a direct object, like deceiving a specific person?

Yes, it often takes an object (like me engaña for "it tricks me"). However, here it is used generally to mean "is deceiving" or "is misleading" to anyone who looks at it. By leaving off the object, the focus stays completely on the tricky nature of the magnet itself.

Why does imán have a written accent mark?

Spanish words ending in a vowel, "n", or "s" naturally place the spoken stress on the second-to-last syllable (like the word barato). Because imán (magnet) has its spoken stress on the final syllable instead, it needs a written accent mark to show it breaks this standard pronunciation rule.