I think it's a flower forming, you must have the right conditions for it, I've seen one on the internet which is an orange colour :o)
Or on the other hand I may be wrong LOL

Your plant is infested with aloe mites which cause these unsightly galls. Best thing to do it to place this plant into a plastic bag and throw it away asap.

welcome to GoY .

sadly this is aloe gall mite [aloe cancer/aloe wart] damage and the mite will affect any others you may have. one source says cut out the infected parts another says dispose of the plant.

as they are relatively inexpensive I'd bin it as suggested by Loosetrife2.

Thank you all for the help. I will be sad to see my aloe go but it is a necessary

Oh! Good to know you have found out what it is, I was looking on my iPhone so pic was small & there was me thinking it was a flower LOL, sorry about that :o((