Monsters/mythical Creatures Quiz

[larkrise]

I'm afraid I'm not doing very well with this. Still got 9 more to answer! Here they are if anyone's feeling clever.
17) Why dragons are found here (5)
18) Born with second silicon chip inside (6)
19) Collapses round acidity indicator? (6)
22) Krypton rifle in French (6)
23) Cake with singular twitch (6)
24) Alternative ten (3)
25) Most of crime writer needs gravity (7)
28) Treasure - Brecon's the place if you return (8)
29) Soldier standing before a city (4)
Many thanks.

[mac44]

18. Nessie

[shoota]

24 Orx?

[pixie373]

19 s ph ynx

[bibblebub]

24) ent https://en.wikipedia.org/wiki/Ent

[Frank97]

22, Kraken

[bibblebub]

17) hydra

[bibblebub]

28) Cerberus

[Psybbo]

17 hydra?

[Frank97]

29, Gila

[pixie373]

25 chimera?

[Frank97]

23, Bunyip

[larkrise]

Thank you all so much for helping. pixie373 - thank you for sphynx. I don't think chimera can be right as I've already got if for another answer ('Ringing bells for an artist'). bibblebub - I'd never heard of an ent before! I don't get 'cerberus'. Would you mind explaining that one? Frank97 - thank you but I also don't get 'kraken'. Kr I guess is for Krypton rifle but why is aken in French?

[pixie373]

You're welcome. I wasn't too sure about chimera either. Will have another think.

[Frank97]

Kr - Krypton
Ak - AK47 rifle
En - in, in French

[slaney]

25. G RENDEL(l)
28. Backwards in clue.
22. Rifle is AK + EN (in French)

[Calibax]

Cerberus - hidden backwards in clue
TreaSURE BRECon

[larkrise]

Wow, very clever. Thank you Frank97 - now I get it! Thanks also to slaney and Calibax. I can't believe it's all finished now. Thanks again to everyone.