Lump in concrete floor

[Tentontousand]

Over time I've noticed this lump forming in just one area of our floor... First I thought it would be a leaking pipe but there's no piping under that part and our boiler hasnt experienced any pressure drops. I believe this concrete floor was laid down like 30 years ago. Any idea what it could be?

Also, what's the best way to reduce this? Chisel it down and level with some leveling compound?

 

[jj4091]

Is the lump definitely in the concrete or is the flooring distorted?

 

[foxhole]

Looks like heat distorted laminate.

 

[Tentontousand]

Looks like heat distorted laminate.

It's vinyl but it's bulging under that

 

[Tentontousand]

Is the lump definitely in the concrete or is the flooring distorted?

It might be the screed on top? I'll pull it up soon.